The miltary can not change your job specialty if it has been specified in your contract unless you fail to meet the requirements of the contract. In other words, if you fail to learn and complete your mission required by your job they can reassign you.

As for education opportunities, there are many. You even get scholarships from the different branches before joining if you want to go the officer route. Then there's tuition assistance, GI Bill and like the Army told you, you can be sent to college while serving. I did.

When I joined, I had a BA in fine arts and since joining picked up a degree from SU in public communications, so it can be done, but is not easy if your job makes you work a lot of hours.

I will refrain from posting my opinions here and keep my posts fact based. If you want my opinions, it will have to be privately.