Diving and fish tanks both are actually on the top list of things to naturally relax people and lower blood pressure. Diving is not a physical hobby unless you wish for it to be. It ranges from "Scott" who has no use of his lower body. To me who wants to try it all. If you can walk to the end of the street you can dive in a manor of speaking. Most diving is mental and preparation more than physical. Emergency and extreme situations can arise anytime you are under but if you practice it and are prepared for it you can both remain calm and go on with it. Do what you feel comfortable with and if you don't like it don't do it. I took my mom skydiving a couple years ago. She was 52 at the time and loved it. I have tried to get her to dive but she will not yet and I don't push it. She hated water when I was young but we had a pool and boats. We all learned to water ski, kneeboard, etc. Not mom she didn't like it. Then she seen some pictures of us diving and went snorkeling with us. She is now hooked on it but still not diving but one step closer. She has played in my pool with dive gear but still isn't comfortable enough to go do it for real. I don't think it's far but I could be wrong. I myself am upset that I didn't start sooner in life. I feel as if I missed something and could have seen more. I am only 30 and hopefully have many dives to go but wish I had done it when I was younger. However I was a bit stupid in those years so it all worked out for the good most likely.
The one thing to remember is that you should never stop going and never miss out in life. Who cares how old or young you are. If you are healthy and want to try it, GO FOR IT. Besides all else it would suck to die wondering how fun something was rather than die know how fun it was.
My Outlook to diving...
I love it beyond anything I have ever tried. The list grows from drag racing, monster trucks, tractor pulling, ATV racing, MX racing, dirt track racing, sky diving, and plenty more extreme sports. I have never found a more intense sport that was so relaxing. If I die underwater hopefully it was somewhere warm and I sink so I provide some more food for the little fish. That would be a dream come true.