If you're a young hunter, you definitely need a .22. It will help you get used to the rifles and to future, more powerful cartridges. A choice would be any model of Ruger's 10/22.

Optics are not needed for a .22, in this case.

Gear (camo and calls) is very important. The camo helps you become part of the landscape and prevents the animal from seeing you. Using calls you can attract the squirrels quickly and efficiently. It's a good thing to buy one.

For choosing the best rifle, go to the local gun shop and try some, if possible. You could also join a hunters' club, they could give you more tips.