The Mini fits into your category perfectly actually. 0-60 in 10-11 secs, depending on who you listen to. Most 1275's put out about 60-70bhp stock, very easily tuned though, especially the carb'd ones. BMW do a supercharger that you can pick up second hand for ~£400 for example, has been known to triple BHP when setup correctly in the right engine. It'll out-handle literally any other "first car", especially if you fit 10"s, and can take most in a straight line. It has been known to take the odd chav in a Corsa by surprise when going around roundabouts
Motorways aren't that much of a problem, you can get them up to 90-95mph before your ears explode, but it's going to be fairly wobbly at that. 70mph is definitely possible, and it tears away fine at about 4k. One problem is speed bumps (they have 14cm clearance as standard, nearly all are lowered through wear and tear, or purposefully), but you can fit between them so it doesn't matter
Plus it pulls like there's no tomorrow. Take it into town any weekend night, and if you come home with an empty car there's something seriously wrong. And it always has reserved parking spaces where no other car can fit. Tescos trolley bays work nicely
It's like a road legal go-kart, if you're doing 40 it'll feel at least 50, which is very handy as a first car. Most people will beg you for a spin in it, everbody seems to love them. It actually has plenty of driver leg room, not so much passenger leg room though. That's a good thing though, watching tall people get in/out is always brilliant. Even more so if you fit buckets
I'll stop talking about the Mini now as I've been ranting a bit. Oh, if you get one, pack several jackets when you drive during the winter months. You'll thank me when it happens
Avoid the ZR like a house on fire though. Aside from being less comfortable than sitting on a pile of bricks, the few I've seen have been plagued by engine trouble. The lad I bought my Mini off was trying to flog a ZR, blew 3 head gaskets in the last month on him. They're far more trouble than they're worth, a nice Metro would be a far better MG.
Seriously, any car will be fine. You're not a professional racing driver, you're 17. You don't have the experience to drive a big car properly (No offense mate, trust me, I'm in the same boat). You wouldn't believe the fun I've had in a 1L Yaris, it's not all about engine size. I've had a nice few close shaves in it, that I know I wouldn't have escaped (and probably wouldn't have survived) in a bigger car. By bigger car, I mean both engine size and physical size. It's far better to get a small-ish car know, rack up the experience on the road, and then get something with a bit of poke as a second or third car. Actually, the Yaris is about the best first car I could suggest. As a 1L it puts out just under 70BHP, and 0-60 in 12.5s
OK, I'm really going now. I've just spent the last 20mins typing this on my phone