I am a full time Porsche only mechanic. I'll give you my opinion.
I started my mechanics career in 1985. (I will be 54 this year) Before that, I was working the parts counter at a hot rod VW shop. I also did a short stint working at a Porsche dealer in the parts dept.
Working on cars is very tough on the body! I get a good laugh watching some of our customers come to the shop to work on their own car. They are absolutely spent physically after a day of it. Now try that every day!
Buying your own tools! I have over a quarter million invested in mine. I have probably helped my Snap On dealer put his kids through college! The gal that cuts my hair probably has a thousand bucks tied up in her tools...and probably makes more money then I do.
As others above have stated, You will like doing it until you don't.
Working for cars is not for everyone.
Hind sight being "always" 20/20, I should have stuck with what I was doing when I was 18. I was an EMT back then. Had I stuck with that, I would have gone on to be a Paramedic and probably be retired by now.
Not trying to tell you what you should or should not do. The above is only my hands on opinion.