Is this age gap (read body text) bad? If it is, would ppl genuinely care abt it?

Alr so I’m 15, and in 10th grade. My ex boyfriend is also in 10th grade in a diff school however he started school 2 years late so he’s 17

I heard rumors that he’s talking to this girl and like the only thing I care abt is their age gap

The girl is 13, and she’s in 8th grade, she’s also in his school

Please don’t come for me saying I shouldn’t be looking at my ex and who he’s talking to but teenage ladki Hu main 😭🙏 and I rlly don’t care much it’s just this age gap is weird and my friends all have odd opinions too some r like it’s fine some r like no it isn’t

But idk I think in our society age gap is not talked about much? And ppl usually don’t care? So ig even if they did start dating I don’t think others would fine it weird

So is this 4 year age gap (but only 2 year gap in grades) necessarily bad?