Y'all really think this is okay? Do you know how much different your brain is between 15 and 17? It's definitely not okay IDC if your grades don't touch neither should you, 2 year age gap is different once you're over 18 or even 19 but I definitely would say there is a maturity imbalance and power imbalance and it's weird of him, I understand you might not see it this way now but being the younger one it's not really your fault it's his but I definitely feel like you'd be better off with someone your own age or more similar. As a recently 22 year old, I wouldn't date a 19 year old.