Can. not having sex do any harm to my system. especially if i always watch porn.

Many live without: Although many people do this regularly, ejaculation (orgasm/climax) is not a requirement for life. Unfortunately for some, either due to illness/age/religion, or life circumstances prevent such pleasure for many many years. So, if you don't feel up to it, then you shouldn't...You are only 25, the real opportunities will come...Good luck.