First off welcome, its good to see more hobbyist joining the community,
Personally after using both Alice and Unity, I would tell you Unity is a million times better than Alice, but your probably shouldn't start with it.
Alice lacks many features that Unity has, but it far simpler to learn and use. Alice provides a simple way to learn an oop. While Unity is far more complex and will most likely give you a headache.
Understanding Alice really helped me with learning Unity and still does. Many of the simple versions of things Alice has Unity has too just more complex versions of those things.