How many years younger should be a girlfriend for me? A girl told me she has to match my age! Your opinion, please =w= (I think up to 9 years and 6 months, like mom and dad)

well the older you are, the lerger the age gap you can have, but 10 at most even for then.
id say for your current age, 4-5years age gap is fine ^^

____+'*~:Ask me anything!:~*'+____( ` ¬`)b