Where are you located, i can help you out. No one gave you good advice so far with a few exceptions. Dont buy anything yet. First thing you need to do is find a kart track near you.
Watch a couple of races and ask around im 16 and kart. Its never too late and the number one important thing to do is get seat time. Its very important karting has a very steep learning curve and most people quit in a few years because they get fed up.
Go to your track, see which classes are the most popular and cheapest. I suggest the kt100 4 hole can class.
Check
www.ekartingnews.com and look at the classifieds, browse around. What is your budget? You can get a good package with everything you need plus spares all for under 2k if you look hard
good luck!