Beccie's climbing partner is her dad, Rob.
He started taking her hill-walking when she was just six months old, tucking her into a special backpack.
"I call her a mountain goat," he joked. "She goes scrambling up places and seems to get more powerful the higher up we get."
The three peaks will be quite a challenge, but Beccie's got her sights set on much bigger things.
She wants to be a mountaineer when she grows up and fancies taking on the world's highest peak, Everest.