When I'm riding for a long time, my feet will start to go numb, but I just make sure to wiggle things around frequently and that helps a lot.

I'm a fairly new rider and am comfortable riding at a cadence between 80-90, but at any hint of wind or a bump of a hill, I drop down to about 70.

It sounds like you're doing amazing on your first ride. I'd not worry about cadence just yet, and just enjoy getting out there and having fun for now.