I got my Class A at 21:
My advice is to get the license, but dont sign with a company right away. The big ones like Swift, Schneider, Werner, and Stevens SUCK, and for the love of God AVOID WESTERN EXPRESS LIKE THE PLAGUE.
I became so jaded with the trucking industry in a year, that Im currently unemployed and dont want to drive for a living anymore. I fucked up so bad even, that I might lose my license for 4 wheelers :/ Just know that it does bring money, not as much as the schools promise, but I was able to buy a trailer, so I at least don't have to be homeless while unemployed.
If I could do it again, I would get my manual license. Do not let anyone talk you into an auto restriction, it will end your career before it even starts. Also, try to become an owner operator. The schools will shame you for it, but thats because the megas pay them to. Try to get your own truck and pick up your own work, its honestly the only way you'll find happiness in this industry, but it will 1001% bring you happiness. Being an OO might bring less money, but money has never equaled happiness, and having something to be proud of matters more than the pittance any of the megas will give you. Keep in mind that schools will say you're gonna make over 150k a year. Swift starts drivers at 55k a year.
P.S. I love your pfp ^w^