Just curious but why do you say "wanted to be a lineman but THOUGHT you had to be an electrician." Was there a reason you didn't want to be an electrician? Or did you assume you had to become a journeyman electrician before starting an apprentice line position?
In my opinion, if you can answer this question, then your decision is clear, Can you afford to fail (as in, if you do not finish out, will it be devastating to yourself or your family.) If you can, then I would say go for it. It's a great job with great pay, and I love going to work. I wouldn't say the technical part is easy, but it def doesn't come over night and rarely do you understand it the first time you are told/taught, so the opportunity of failing out of an apprenticeship is very much alive the entire time. Prepare for the worst, hope for the best! If you can afford to give it a shot and possibly not make it, hell yeah! Give it a go, you wont be able to say ya didn't try!