Do guys not understand what taking it slow means?

Some guys are a little slow, when it comes to the meaning of "taking things slow". Seems to me you need to find a slightly more mature guy, but I'm making a judgment call there. Maybe he's really swell, and he thinks he doin you a favor by trying to deliberately do what you told him not to do.
So yeah, like the leg dude said, say "WaooW", I'm not into that right now, maybe in a couple months. If he sticks around than you know he's for real. Then of course you may decide to change your mind, and make it sooner or later. or never.
Also.sounds like he doesn't know the meaning of foreplay. a very bad sign.

They will if you if you're consistent in what you say so that they know you mean business. LIke in your case, when he started pulling down your top and trying to finger you, I hope you told him like. "Woahhhhhhhh! . Don't you remember what I said before about wanting to take it slow?" If you did then I think he got the message. The trouble with a lot of girls is that they say one thing and then soon forget what they said and let the guy have his way. Don't ever be made to feel like if you don't let them do as they want, they'll leave you. In those cases you're far better off to just tell a guy that has poor hearing that you're not that easy, and for him to just move on and that you'll manage just fine. If he's really sorry, then of course you still want him.

Only idiots don't and, clearly, this jerk is an idiot. Find another man who can keep it in his pants.

He might have thought you meant emotionally. Like not feeling too serious about each other too quickly. Either way, as a girl you need to realize that guys always want sex, and you have to be able to deal with that.