Does she throw a "heavy" ball?

All things equal in terms of velocity any down ball is going to seem heavy due to the downward component. A couple of seasons ago the hitters at SC would refer to the drop thrown by Nikki Blue as heavy, especially when compared to Jakes 2 seam and rise. They said hitting the drop coming in 68-70 mph was like hitting a bowling ball.

Congrats on your first day of Catching 101 class.

Certainly, a 60+ "fastball" and any derivative with peel spin can brighten up the horseshoe of the hand quickly. As riseball mentioned above, you're mixing the combination of gravity with spin and speed. Eventually you should find the mental compensation for break the more you play catch and become comfortable with it. A little trick is to try to find the right time to soften the impact with a quick little glove pullback motion just before contact.

A heavy drop is just a saying that can describe the combo of good speed, spin as well as location. Hitters may be consistantly swinging over the top of balls they "think" they should be hitting. If it's working well, you may hear a hitter say something to the effect that ball is "falling off the map", etc. When you hit a "heavy drop", it can feel dead or like you're hitting into a punching bag because the contact point is so far toward the end of the barrel. Because of the end contact, the barrel path is deadened which is transferred up into the handle.

Until you find your mojo, try a batting glove, foam rubber, piece of leather, etc.

Chris