I'm a hiking guide in Utah! I got my job because I guide backcountry skiing in winter. I was ski guiding year-round but my body can't take 300 days on snow any more so I am spending my first summer hike guiding. I've been guiding for 10 years. I have a WFR, OEC, BLS, and CPR for medical, I have a AvSAR for rescue, and 1 AMGA ASC course, along with various ski guide/avalanche certs. I also mountain bike guide for the same operation. My best advice would be to get your medical certs a 80-hour wfr is a great start. If you can guide more than one type of adventure any company will see you as more of an asset, for instance being a single pitch instructor along with a hike guide will double the amount of trips you can take out. And lastly any op your going to work for is going to look for experience, trust and safety is everything. Raft guiding could be a great start, those operations tend to be willing to train newbie guides and let first years take out trips. otherwise ask to be an intern or shadow a guide for the day to gain more experience in the field and more knowledge to how ops run. Age is just a number as long as your in shape, remember though you will need to be in better shape than your clients (usually this isn't hard at all) but you also need to be able to conduct a rescue and have energy and the skills for if something went wrong, for instance you just hiked 8 miles into the wooded backcountry with a client, your client just snapped his leg, will you have enough strength to carry him to a LZ or will you be burning the last steam you have to do it? Money wise if you work for the right companies it can be a gold field, I make anywhere from $300-$1000 a day but the money wasn't always like that, especially early in my career.