10 1/2 months is not too young. Under 6 months I would be cautious, but I have friends whose kids got the pox at 3-4 months old and they were fine. It wasn't intentional, but you can't always control these things.
So, when IS it going to be a good time to "deal with it?"
That was my DH's objection when I exposed our kids right before Christmas, but then I pointed out our oldest was going on TEN and the longer we wait the more likely he is to have a really hard case. As it was, he had a fairly mild case, then rest of them came down with it 2 weeks later, and because of the CP we had a very relaxed holiday season with no rushing around from relative to relative, and no scurrying and scheduling conflicts with different holiday parties.
And oatmeal baths. Lots of oatmeal baths.
I'm so glad the CP issue is *case closed* for us now.
Anyways, at least you have a few more years before it becomes a concern. I was worried that DS might get another year older before we heard of anyone who was even open to the idea of letting us come over for intentional pox exposure.