My Uncle was a welder- and he was good enough out of it he was invited to work on the Hoover dam construction . One of my brothers is a union iron worker, so he works 50 stories up sometimes… From what I can see it’s hot, dangerous, sweaty, and critically important to the infrastructure we depend on. Gisèle is spot on about quality of work. I’d add that spending time with older welders who are willing to teach you the skills as one of the single most important things you can do if you really want to a good at welding and make a career out of it. Third, Learn and use every safety regulation on the job!
I’d also recommend you consider taking yoga or tai chi specifically because the better your balance is the safer you’re going to be in a welding job whether you’re on the ground or 15 stories in the air.