Hello Alex,
You can use your driving license to drive in the
USA as long as you carry your license with you at all times.
The US authorities allow you to use your countries
driving license as long as it is written in the Roman alphabet language so if you are from the UK, you should have no problems.
There are age restrictions when renting a vehicle so, you will need to check with the particular car hire company.
Hope this helps
VacationBuddy