The limit to the number of port groups per vCenter is 5000, but you don't sound like reaching it.
Really, for the number you've got (7) you're a pretty small network as far as standard implementations go, and you'll be fine.
I do think it's worth looking at whether you really expect to be utilising all six ports - it's rare for aggregation to achieve actual performance increases beyond two, and often "more" is not better.
LACP changes things somewhat, but it doesn't apply to many environments.