Just do it. Even the mistakes that you make can be benefits when you allow yourself to learn from them.

Don't get intimidated over what tools you need. You'll be surprised at how far you can get with just a 5mm allen key. Pick up whatever other tools you need as you find need for them. Step up in quality when you buy a cable cutter because you'll use it a lot and a cable cutter that leaves one strand uncut is a PITA. I learned to tune bikes hanging my bike by it's front wheel from a garage rafter.

Good luck! Have fun.