If they will let you,, go for the class A,,, get all endorsements and keep them!!!
Hazmat pays better an there are a lot more companies hiring for hazmat in case your job goes south!
The written tests will be mostly about class A anyway so no reason not to get it,,, unless your job doesn't want to go that route,IE they won't furnish a tractor trailer
I got it all back in 1983 but let my hazmat go,, now it's a pain in the butt to get,,, have fun stay safe and keep it out of the ditches!