Lindsey-
Around that time, a lot of babies start getting ready for the transition to 1 nap, but aren't quite ready to make the transition. If she's happy with a shorter AM nap, and is still going down easily for the PM nap, I'd go with it for now. Increasing her awake time in the morning will only push the rest of her day later, like you said, and will only help if you are in fact working toward eliminating the PM nap.
When Tyler was about that age, he was getting tough to put down, so I tried transitioning him to 1 nap. It failed miserably, he just wasn't ready for that much awake time yet. We went back to 2 naps, but they were always short naps...never more than 30 min for the AM one, and rarely more than 45 min for the PM one. It stayed that way until he just wouldn't take a morning nap anymore at 13 mo, and the transition to 1 nap was pretty easy.
If she's happy, I wouldn't worry too much about tinkering with her routine just yet!