It depends a lot on what school you attend, but a lot of the vo-tech type schools will allow you to leave up to 6 months before graduation to go find a job. You just have to complete the book work and turn it in, you'll still get your degree.
Heck some companies might even be willing to help pay for school, or let you work in the late afternoon.
For what it's worth, my Dad was an appliance repairman for 30+ years when he switched into the HVAC field (old company went out of business). He learned some of the basics from the window airconditioners, but roughly 7 years later he's one of the top techs where we work.
Never say never. Never say I can't do it. If you must ask a question like that, just ask why couldn't I do it?
Enjoy the advice from yet another newb