There are a lot of variables that go into the cause of tongue bite/burn, but to answer your question as to whether or not it is normal, I would say that depends on how long you have been smoking. When I started out, I never so much as smoked a cigarette, so I found myself somewhat susceptible to tongue bite because I was fairly sensitive to the smoke itself. That sensitivity does lessen with time. I also made common beginner mistakes, namely smoking goopy aromatics, puffing a bit too much, and just generally being impatient if I had to relight several times.
It is one of those things that gets better both with time and practice. It sounds like the tongue bite you experience now is less than when you started out, so that sounds like progress! I wouldn't fret too much over minutiae, such as the exact amount of time you spend on a single bowl or how many times you have to relight. Be patient with yourself. It is worth it.