johnb,
I was in my late 30's when I became an electrician. I don't regret it. But I want to tell you what your up against. I'm now 48.5 as my username gives away.
I knew I was behind my peers so I've always, and even still hit the books hard, in order to obtain knowledge comparable to those my age, who have 10+ more years in the trade then I. Still when applying for a job (one that requires a more "seasond" electrician) there always seems to be someone with that little bit more experience than me, and he gets the job. Or they have all the qualifications, and are 15 to 20 years younger than me.
Discrimination for age is illeagle. However it's done. Many ECs would rather hire a qualified electrician that has the least potential for health problems, is the most physically fit, and will work for the lowest pay. Even more so in residential. One shop I worked for, with 12 guys, had no one but me that was over 30! (I was only hired as fill in help). So of course they were not interested in keeping me on.
As far as the union. I've been told that I could never be in it long enough to gain a decent retirement pension.
I've done the best with BRAINS REQUIRED work, like service work of all sorts. And have done the worst working for ECs on BID JOBs. "I'm loosing money, its your fault" the battle cry of the bid job.
I was once told in this forum that by now I should be a "shop rat", and be constantly employed. Implying that the problem is me. In todays turbulent economy, thats an unrealistic statement, probably made by someone who's lucky enough to be a shop rat.

I've had recent job offers. But they require so much of my time and skills, to grow their companys, that I saw no difference in being self employed so thats where I'm at and happier for it.
RAW