Following the ultrasound, her doctor suggested she might only have one kidney - a diagnosis that was confirmed by an MRI scan.
But when revealing the diagnosis to Cassandra, the doctor also informed her that she has two vaginas, two wombs and two cervixes.
The condition, uterus didelphys, is also known as double uterus, and occurs because the uterus starts out as two small tubes in the womb.
Cassandra, who also works as a model, said: "When we got the test results back the doctor said I only had one kidney and flippantly added that I have two vaginas - as she suspected.
"There is one vaginal opening but inside there are two vaginas, two uteri, two cervixes.
"Most vaginas are one large cavity but this is a complete separation into two different cavities.
"I was shocked and the doctor explained to me that it was like an upside nose.
"I didn't really know what to make of it - I was just in shock but I don't really let it get in the way of my life.
"It certainly helped explain a lot of things."
While the condition may not lead to her being unable to conceive or leave her more susceptible to feminine cancers it can lead to complications.
Cassandra added: "Ever since I was younger I would go to the doctor because I was bleeding for 28 days or I would have two periods a month - but they never suspected I had a second vagina.
"I always had really bad cramps - I could not move or my bowels would just not want to behave because the cramps were so bad.
"It is extremely difficult to deal with because you don't know whether your period is going to last a week or three.
"As far as my understanding of how it affects a person's sex life - for some people having two vaginas can make it very painful - for others I assume there are more nerve endings so it could be more pleasurable."
Cassandra added: "I'm definitely nervous about having to explain this to future partners. It's not something I'm looking forward to.
I didn't really know what to make of it - I was just in shock but I don't really let it get in the way of my life.
"It's obviously a huge deal and I have no real idea how this is going to affect my life so it's something we would have to talk about.
"But hopefully it won't be an issue - when I do meet someone I'll be looking for an emotional connection, somebody to laugh and joke with - the sex side of things isn't a huge issue for me."
Despite the rarity of her case Cassandra found her family very supportive when she made the announcement.
She added: "I kind of walked in and said, 'guess what mom I'm twice the woman - I have two vaginas".
"She really didn't know what to say and my dad was really shocked.
"He's a math guy so was trying to figure out how this would even be possible but they're cool with it.
"It's no real issue for my friends - I just tell them that I'm pretty special but they just see me as Cassy - not Cassy with the two vaginas."
Cassandra's YouTube channel became a success when she began making videos about her chronic acne and how she covers it up - with the most popular one gaining over 25 million views.
She said: "I got my first pimple at eight or nine years old and kids would make comments about it.
In just a few short months she developed a large following of subscribers but it really took off when she published a video on how to cover acne with foundation.
She added: "So far it's got around 26 million views and it just keeps going - I posted it shortly after launching the channel and that's when I knew how big this thing could be - how many people need this help, advice and support.
"My subscribers went up over night and I started to get calls from the mainstream media - it was like a whirlwind and things haven't really slowed down since."
Dr Harris, told Cassandra, the condition shouldn't cause her too many problems in life, despite being very rare.
Dr Harris, told Cassandra, the condition shouldn't cause her too many problems in life, despite being very rare
Cassandra recently modelled for the brand Boy Meets Girl at New York Fashion Week and is starting to get more work as a model.
While in the city she visited one of New York's top gynaecologists Dr Dena Harris to discuss her condition.
Dr Dena said: 'A lot of women do not even know they have this condition and find out when they're pregnant - It's possible it won't even bother Cassandra in a sexual way.
"There's a possibility there will be some issues with getting pregnant for Cassy - but if there's a problem it can be dealt with but we would hope she will be fine.
"I don't think she will be more susceptible to feminine cancer based on her anomalies and I don't think that there's any correlation between Cassandra's acne and her vaginal abnormality - but I can't be sure on that.
"Women develop two vaginas when the embryo is developing - it separates into different parts and fuses - if they don't fuse all the way you can get two uteri and two vaginas.
"It's very rare but Cassandra can live a normal life and if there are any problems we could work to fix them."
Cassandra's acne has improved slightly over the past couple of years and she puts this down to her healthy vegan lifestyle and abstinence from drink and drugs.
"My two vaginas can be treated if they need to be and that's good to know," she added.
"But it's not causing problems and I'm not trying to have kids right now but when I do decide I will hopefully be able to have them naturally.
"I'm feeling pretty calm about the whole situation."
While treatment will be available for the condition in the future - Cassandra is resolved to focus on her YouTube channel and helping those who may have faced similar obstacles.
She added: "I would love to continue educating people - I've always been extremely passionate about helping others and I want to continue showing people how to find their own self confidence and success."
- Daily Mail
