I agree with Jim and TJ, you can watch just about any video of a shifter on a sprint track and see just how intense it is. With your only experience being rental karts, a 100cc will be plenty to get used to. Especially on a limited budget if that’s what you said.
Road racing can get you the speed thrill just like a shifter too. And in NoVA it’s local too. There’s a fairly strong KT100 crowd too, and with an enduro kart it’s a great way to get started.