I don't have an aerobird, but I have a T-hawk and they are mostly the same design.
First, check your landing gear. If they aren't on straight, it's going to make your plane turn one way or another regardless of what you do on the stick because the aerobird doesn't respond very fast at those slow starting speeds.
Second, make sure your control surfaces are level. If one of your v-tail surfaces is off, it could make the aerobird turn once you start going down the runway.
Third, be sure you are taking off directly into the wind. The aerobird is a light plane and it will want to turn into the wind automatically.

Hope that helps