no way is that too old. the only thing stopping you from learning anything at any age is the mentality that you cant. I skated from like 10 years old till i was 13. quit completely until i was 18. almost had to re learn everything, and after a couple months i was way better than i was before i quit. if anything being older can help you learn things more effectively, especially if your completely new, you set a better more effective foundation.
a good friend of mine started bmx at 22, and is now like insanely good at 24, like if he were to persue it as a profession he definitely could. Im constantly trying out new sports and hobbies, around this age is the best time to find shit you like to do and do it. the people that think things like skateboarding are "childish" or make other excuses to not do them after 18, are the people who are completely grown up at like 25 and waste the rest of their life being mediocre, bored and sad.