I am 2.5 years in and still hitting my head...ugh
Anyways, important things are do not get hit a second time!!!!!! I cannot say this enough!
If you think you want to push yourself then do the athletics, nothing where you will jostle or hit your head again, but anything else is fine. Just take it slow and give yourself the breaks you need. Some will say this is wrong, but I think going stir crazy is worse.

Good Luck!
God Bless!
Margarite