A lot good advice here for you.

I'll give you a little of mine.

Go talk to a couple different school counselors. They can give you an idea of what is expected. Ask if you can do a little job shadowing with them for a couple days. It would give you a great chance to see the day to day workings. Try a couple different schools and counselors.

Do the same with a Diesel Tech. Call up a couple heavy equipment places and talk to their service managers. Tell them you are interested in becoming a tech and would like to see what is involved and see if you can job shadow a couple times.

When my wife was trying to figure out what she wanted to do, she job shadowed at a couple places and it helped her out a lot.

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1992 Ford Ranger STX
-2" lift
-31" Treadwright Crawlers (yes I run retreads!)