Is it really strange of me to still have the mindset of a high schooler even though I am about to graduate college after few months?

Yeah I am 21 but I feel and act as if I am a 14-16 yr old boy. I am about to graduate college after few months but I still have the mindset of a high schooler. I try to pick fight with guys in my class in college for fun but they don't even take me seriously. They are all in the 21-24 age range and also I make intimidating sounds near the guys who are my juniors in college. I also got a crush on a few girls in college who are my juniors in 1st and 2nd year but I am too shy to approach them and I imagine and wish they were my girlfriend. Similarly on the dating app too I am sure the 18-25 age girls ignore me maybe because my chatting style is more similar to a 14 or 15 yr old and my flirty lines are too cheesy. Also lately I have been getting moody nowadays and suddenly feel like crying whenever a sad song comes in my mind which are probably more common in teens than someone in their 20s.