start with cleaning your room and then work it from there,sort your life out,the reason you feel shame and guilt is...deep down you know the problems that need dealing with to restore pride and self respect but you choose not too for certain reasons

the fact you can see you are childish shows you have already matured,your brain is telling you to rise to the challenge of manhood and you are resisting it and that gives you an uneasy feeling all day every day i bet? i know cause i was like you once and now i have 2 kids

dont just make excuses so you can remain where you are anon,you clearly have desires for a family of your own...but you know atm you are not a family man material

do what must be done,get a job,lift some weights,get a make over and new wardrobe etc if anything have this convo with your dad and tell him you desire to change he may just be the person you need to give you a kick up the arse he is only hard on you cause he percieves you as a failure,ask for his help and prove you are not

do you wanna be a man with family,a son you can bust out the NES with and experience a side of life never seen? or remain sat in your room fapping to cartoon horses like anon above mentioned and listening to linkin park and brooding?

they call people like you "late bloomers"