Living with your parents is kind of tricky. I mean, it's nothing to be ashamed of: I'm 22 and I'm still living with my parents - I moved back in after uni so I could do my MA. And I know a lot of people who've done the same, or simply moved back in in while they find their feet.
But I do think it's hard to be your own person, and to feel remotely adult, while living with your parents. I find myself regressing to being like a stroppy 14 year old. And, personally, I find it near impossible to have a relationship while living with my parents; the two things are just not compatible, at least not at this age. Not because of sex or anything like that, just because I don't want my parents knowing every detail, and because I don't feel independent enough to be in a relationship while I'm living at home full-time.
You might find that once you start uni you feel more confident and like your own person. I think the important thing is just to do things at your own pace.