I really want to date this girl I know! I really love her (I am 17, and so is she)

My mom says its not good to date unless you are serious about it (which I am) and can do something about it. (Getting married) and because you can't when you are 17, it's not really worth dating.

Now, if I was old enough, I feel like this is the girl for me, (I am pretty sure she likes me too), I most likely would end up asking her to merry me. (I am pretty serious about this girl) and I say that, trying not to sound really stupid about the way I feel.

My mom, just thinks its a bad idea!!

The only thing she would let me do, is invite her to our house. But that just seams really weird. (I have 5 siblings at home right now) I would not be allowed (meaning, my mom wont let me) to be alone with her, and I would feel really awkward, just sitting with all my family. Who knows how she would feel.

Some help please.