I don't know what happened to you, but I suspect a combination of the effort of swimming in moving water, it's much more effort than in a pool. Coupled with the constant slapping of chop in your face meaning you need to really lift your head up high to breathe... yeah... it's scary. Glad you got out ok.
Worst part of that job was when you count the kids, 4 in that group, 5 in that group ... now there's only 3 in that group. Where did that other person go?
At no point have they made me feel safer for being there, unless they're doing it as their full time job.
The certificate takes 6 months of study and includes a full first aid education, as well as water-specific first aid, what does drowning look like, how to swim against a rip tide, how to tow someone who is either dead weight or thrashing or larger than yourself. They have to be able to swim 1 km with a time limit. They have frequent training drills and go for refresher courses every year or two. And the pay is quite a bit better than normal kid jobs pay. Think 10-12 per hour for a grocery store or fast food job, and 17-19 per hour for lifeguarding.
I only know two or three friends who have done it, but they are fairly impressive people, to me. I can't speak for all lifeguards of course, but I always felt pretty happy with the supervision of my 17 year old friend Michelle, for example, when the 6 kids in my care at summer camp were splashing in the lake.
Anectdotal, but I was a lifeguard in my Highschool years nearly 2 decades ago. Scrawny at 5'9 140 lbs. However, we spent a lot of time training and practicing rescuing people. We made sure all our staff could individually rescue someone that is 250 lbs+ across the pool, tread water holding bricks over our heads and swim respectably fast, trained how to scan the pool so that there are overlapping eyes and no blind spots on each area. We were all CPR certified (however we deemed the lifeguarding a failure if you've already needed to resort to CPR due to drowning). We spent hours practicing loading a victim with a spinal injury in water onto a backboard (spinal backboard procedures), and even had EMS stop by to train us on first aid. Refreshers on procedures and training were done quarterly.
When not at the side of the pool, we're cleaning bathrooms. Good times for minimum wage. Even saved a couple of kids that wandered too far off into the deep end during summer. No one even noticed they were drowning.
I hope at least some of this provides you with some trust to your local lifeguards even if they are young.
If those are indeed requirements even for part time lifeguards, then it makes me feel much safer.
Interestingly CPR success rate is really low (around 20% I seem to remember.) We're all told that. After a couple of breaths into the patient, if they don't start coughing up water and sit up, then you're not likely to save them. So the qualifications don't matter so much as speed, strength and attention.
You should be the first one responsible for your own safety when going out swimming.
I used to swim in rivers with no supervision, and obviously I needed to be very careful not to get myself into a situation.
I wonder if there's sometimes a risk compensation problem from the presence of lifeguards -- forms of "I don't need to be so careful, the lifeguard would save me".
https://en.wikipedia.org/wiki/Risk_compensation
https://en.wikipedia.org/wiki/Moral_hazard (less directly applicable, but kinda)
Like I said in my previous comment, if you get into trouble it is very hard to see you let alone get out to you and save the day. You are responsible for your own safety.
We used to red flag the beach (no one in the water apart from local surfers) then at the end of the day take the flags down and get ready to go home. Every time some idiot would go in for a swim... as if the flag was the thing that made the sea dangerous.
If you go in the sea, be prepared.
Saving someone who is drowning isn't about strength, it's about technique.
But 99% of the job is prevention.
You'll notice that lifeguards usually approach from behind the person that needs rescue. The standard response is to grab anything that can help the drowning person stay afloat, which includes the rescuer.
Don't punch them, it's less effective and can knock them unconscious, which can complicate the rescue.
Source: was a trained and certified lifeguard and swim teacher in my teens.