"Realistically we should be in the top ten but horses are very unpredictable. Anything can go wrong," she said. "I just need to be confident and we will see what happens."
The cross-country course at the National Equestrian Centre, re-developed in time for the competition, is expected to challenge riders and horses alike. "It was designed by John Nicholson, he's my favourite course builder, he's amazing," Smyth said.
"The course is going to be big and bold. Horses will have to be straight and want to do it."
The course opens this afternoon for riders to walk, but Skibbereen will see it for the first time when she competes on it on Sunday. "You can walk a course and plan but everything can change once you get there and you just have to adapt."
Smyth thrives on the adrenaline of the cross-country - "that's why we do eventing" - but as a self-confessed perfectionist she also enjoys the challenge of the dressage.
She will spend the winter bringing on her two younger horses, one of whom she will ride in the pre-novice class this weekend, and perfecting her combination with Skibbereen.
"We'll be stepping up to the next level (3*) next season so without the pressure of competition we can fix mistakes," she said.
Longer term, the plan is to head overseas.
"I have been to England twice to work as a groom for [top British eventer] 'Piggy' French. I would love to go back and live the dream competing over there."
And with her partnership with Skibbereen well and truly on the up, she hopes to raise enough money to take the mare with her.
"We get on very well, it's hard to go out and buy a horse that tries that hard for you," she said. "She's become part of the family."