Best thing you can do for your neck or any other part of you as someone new to Bjj is to tap when someone has the sub in place not when they are cranking it to submit you.
Learning to stop them getting the position on you is far more important than escaping it once its on.
Lots of smaller guys end up with neck problems from trying to muscle out of holds by bigger guys. Eventually it will catch up on you.
Neck strengthening and stretching is very important.
The gym I train in always does some strengthening stuff as part of the warmup and ROM stretches after, it really helps.
I also found cleans to have a good carryover here as well.
Hope that helps a little.