Okay, don't be angry! I however, do understand where she's coming from. (My friends say I'm motherly so... yeah...)
Think of it from your mom's point of view:
-You're both young
(For most mothers this enough. "My child is too young
to date. He/She could get hurt or make bad some decisions... etc. etc.")
She tells you aren't allowed to date because she loves you. The probability of marrying the guy is pretty slim (You are young
But! You should still talk to your mom. Ask her where's she's coming from. (Be respectful) Try to understand what she means. If you truly do love this boy then you'll have to be content with being friends for now (sorry!) You should ask her if this is alright, if you are still allowed to be friends (may not
want to add the next part... I don't know. It depends on your mom's personality) because even though you can't date you still care about him.
If you need to talk about this more I'm here for you. You can tell me whatever's on your mind. Good luck! -And hope this helps!