Hi K.,
I would think if he is showing interest now, go ahead. I went to a potty training class at Babies R Us and they said the best time to potty train is between 18-24 months.
The lady teaching the class encouraged you to tell your son for a week or 2 that soon you will be going potty in the big boy potty. Every time you change his diaper, tell him "soon we aren't going to have diapers any more, you are going to go potty on the toilet!". She also encourged buying 1 set of "special" underware that your son picks out himself, and a few other packs just normal white. The day you choose to be the first day, let your son wear the "special" underware when he wakes up. Take him to the toilet every so often and ask him if he needs to go. If he says no, maybe just try for a practice. If he ends up wetting his underwear, put him in the white underware and try for the special underware first thing next day.
The lady at Babies R US had 2 important things to teach:
1. Don't use pull ups as they are comfortable and easy to be lazy in. Why use the toilet if you can just go in your pants?
2. The only reward system to use if any is a sticker reward. Whether it be on a chart or stickers all over his shirt, candy is not the way to go.
Don't turn back once you have started as this sends mixed messages. My son took about 1 week to potty train and did wonderfully. My sister also used this method and her son did very well too. The other thing I had questioned was what do I do in public? Should I put him in a diaper or not. She said not to, that being in public is part of a normal day and just make sure you know where the nearest restroom is. Also make sure you have lots of changes of clothes and patience!
It's a process, but sounds like he is ready. If not now, soon!
Good luck to you!