If a ten year old boy likes a thirteen year old girl what do you do?

Be nice to her of course, but mainly be mature in front of her so she doesn't think you're as young and innocent and clueless as a typical 10-year old...

But the case is not hopeless of course, remember Anakin Skywalker and Padme Amidala from Star Wars? The girl was older and they got along in the end..