i have 2 friends who are 19 and 18, and they are both more mature than me in many ways, but one of them coupled with her 19 y.o. friends ->> i notice a difference.
i am also kinda afraid of being around 19 and 20 year old guys, i fall for them quite a lot, and they are usually immature still haha. i cant resist "young meat".
i sound old. damn.
but did you notice the skin of 20 year old guy and 23 year old ? it's different