I was 20 when I got certified. 21 when I got my advanced certification. I recently was hanging out at the dive shop while they were teaching a class. The youngest person in the class couldn't have been more than 12-13 yrs old. The majority of the students were in their 20 s - 30's. Yes, his can be an expenssive sport, but it just depends on what you want to do with it. If you travel alot, you are not getting the full experience if you can't dive. Remember 3/4 of the Earth is covered in water. Seize the oppurtunity to see what most people will only experience on a plasma screen. Many all inclusive resorts include diving and equipment rental at no extra cost. If you go to these places, you are crazy not to be dive certified. Buy your mask, fins, and snorkel and go do it. You can always rent the rest of your equipment for a decent price until you can afford your own. I wouldn't waste money buying your own tanks at this point. Most of the time it doesn't cost much more to rent a tank than to fill one. Plus you won't have to worry about tank inspections and you aren't going to travel with your tanks anyways. When done responsibly, scuba is really a pretty safe sport. I've broken bones doing everything from rodeo to beach volleyball but never really injured myself while diving. Get to know the guys at your local dive shop. If they don't treat you right, move on to the next dive shop. Most of your dive shops are smaller, family owned type businesses and they will usually fight for your business. See if they will let you hang around the shop and help out in your spare time. This helps them by having an extra set of hands around and it helps you by getting to overhear the conversations about dive sites, equipment etc. Who knows, maybe they will throw a tank at you once in awhile and tell you to go check to pool with them. Free air is the best air!!! If you are here you are already convinced that you are going to be a diver so just do it. I promise it will be a decision you won't regret. Good luck