Hello! Welcome to the forum! I hope you enjoy your stay here!
First of all, if you need ANY help at all, please, please, ask us
Working on a new game engine is very hard, especially when you don't have anyone to guide you, that's why we are here!
When I was first learning UDK I had a hard time, it'll all eventually get better, I promise.
3rd person games are very interesting..prince of persia?
I'm sure there are plenty of interesting unity packages on the Unity3D Asset store, look there.
In terms of the Prince Of Persia sort of style, you will need lots of animating skill, since everything is in 3rd person and nothing can be faked like in first person (legs anim, and arms anim)
Be sure you look really thoroughly through the Unity3D script reference.
There you go!
if you have any questions, please ask