Hey phoelix,
With dedication, and some good old determination you can learn plenty in 4 months. I think you should know though, that it's not really like guitar hero. Guitar hero doesn't involve strings, but learning to play a real guitar does. They can be a little rough on your hands, so don't overdo it at first. Your fingers will let you know when you need a break, and when they get sore it may be best to wait a day before going back to it. Try it then, and if your fingers are still really sore, wait a little longer.

Persistance is okay, and after you get used to it you can practice longer. Just don't overdo it, so you can keep on learning to play. In 2-3 weeks you should have some callouses built up, and as long as you continue to play your fingers won't get as sore. One other thing, learning on an acoustic can be tougher on the fingers, because they usually have a heavier guage strings on them.