Cannabis can have its drawbacks when used to ridiculous excess or by a select few predisposed to the negative side, overall it is the most safe/benign drug out there as far as mental and/or health problems are concerned, much safer than alcohol!
I would tell you 13 is too young but that would be hypocritical as i started when 12. At that age don't make too much of a habit of it, that said, too much caffeine at that age will fuck you up let alone anything else lol. The occasional smoke at your age while not beneficial would have to be the least harmful thing you could do to yourself. The 2 possible reasons you didn't get high are either you didn't smoke enough or you didn't inhale properly, after you puff off the joint take a DEEP breath through your mouth before you blow it out, at your age unless your a pack a day smoker (sadly I have seen a few 13 year olds like that) you should be dying choking on that fucking smoke, DYING, keep inhaling, if your weed isn't total shit and your not a massive cunt then .2-.25 grams of decent weed inhaled properly should get your ass high as shit. As a daily smoker I could smoke that amount and while being far from " fucked up" easily distinguish the feeling from being sober.
To answer your question is it worth it? I believe yes, as a result of drug use and being exposed I have alienated and disappointed the majority of my family, I see that as much their problem as mine, only you can answer that question for yourself, alot of parents will think you are a piece of shit for even trying weed, some will endorse it over alcohol its all relative. If you aren't stupid and you are only smoking on the occasion it shouldn't be too difficult to NOT GET CAUGHT. Massive over indulgence in cannabis (and other drugs I might add) have caused me a few problems over the years, none have rivalled the problems of being caught by people who disapprove.