Also give her some time. I picked up cycling several years after my husband--it was a real struggle to keep up with him (going slowly) at first, especially as he's one of those annoyingly wiry, low body fat natural climbers. But now I descend faster than him, and he complains that he can't drop me on hills any more unless he puts in an extreme effort. We have a great time riding together, and it's a workout for both of us.