Hello!
No! It is not like that, the maximum brain development takes place in the 1st year of life after the fontanelles close during the 2nd year proportionally your other bones grow more than your skull.
By the age of 25 years most of your skull bones fuse and by this time all the sinuses and bone and brain development is complete.
Take care!
I do know the more you use your brain the bigger it gets. The human skull probably stops growing whenver the rest of your body does. Say its different for men and & women.