IT all indicates that she actually needs to nap for longer. You have many options here, depending on her temper and what do you think will suit you both best:
1. Try wake to sleep at the 35 min mark of her sleep. There's a sticky thread that came from a case very similar like you that you might want to check out and see the succesfull story.
2. Try extending the nap with gradual withdrawal. For this option you have two options more:
2.1 Come into the room at the 35 min mark (or if you think it's better, come into the room once she's asleep) and watch her stirr and observe what's happening around the 40-45 min mark that is making her awake. Is she crying out without opening eyes? is she standing before she's wide awake? is she stuck in a crib bar or tangled in sheets? that might solve the clue. Also, by being there you can actually avoid her to wake by start intervening with pat/shsh or gentle rubbing before she's wide awake (sort of a wake to sleep but without you causing the stirrs)
2.2 Come into the room once she's awake and crying for you and do as indicated in 2.1
For this option, which i used with my own lo, i'd stay in the room once i managed him to get him back to sleep. If I tried to leave, he'd wake. About a week later I'd be able to leave the room after he was solid sleeping for 15 mins or more. Then i was able to stop intervening and just shs from the outside and 2 days later he stopped waking then.
3. Don't extend the nap (or if you try extending naps with the 2 prior suggestions and don't succeed at it) and have a super early bedtime. On days you can't extend the nap keep trying with the earlyb edtime to avoid overtiredness.
Remember to try at least for 2 weeks with each method before switching to other cause you might confuse her if you try one thing and the next day you try another. Keep consistant and she might grow out of it sooner than you expect.
Good luck and keep us posted!
