Wish I was going to climb Kilimanjaro, I'm a climber myself
Are you an experienced climber?
I live at just under 9000 ft out West so can't really say if the altitude makes my concussion feel worse as I'm used to it.
You live at sea level so the altitude might be a problem especially as you're not being able to practice climbing to see how you feel.
A lot of visitors here experience issues. I'm not climbing right now or even walking up hill because of all the issues I'm having.
Have you spoken to a Dr?