Simple question

kay this is the question that is very debated with no clear answer what is the limit in age difference between a guy or girl for it to be morally right/wrong like we know the extreme were 40year old + 20 year old is well usually not that well but the cloudy area is what I wanna know say

you're 18 is +/- 2-3 years ok? like 15/16ish?
or
19 is +/- 3 years ok? like dating a 16 year old?

some people before were like if you are
14 the oldest is 16
15 the oldest you should date is 18
16 is 19
17 max 20ish
and 18 + anyone older is fair game?

I'm 18 at the moment is dating a 15 year old wrong? we are both about to turn 19/16