hi there-are you rushing in right away when she wakes? you may want to give her a minute or two to see if she settles back herself. I went in today after a 45 min. nap too soon and regretted it as I assumed DS was standing but he was lying down and I think he may have settled himself.
Also, is DD able to stand in the crib yet, or sit up? If so, you don't do the PU part, just the PD part. Wait for DD to sit or stand up then gently lay her back down. Instead of shhhhing since it bothers her (starts to bother babies after 6 months), use reassuring words, "it's okay, time for sleep".
And yes, if she is doing a "mantra" cry (settling cry) and not an all out need me cry then you leave her. At the very least, move away so she can't see you. I find my DS often gets distracted by my presence.
Lastly, how long is she awake before naps? Please post your approx. routine. She may be ready to be awake longer and that will make her tired enough to sleep longer than 45 min.