yay!
if she has a good first nap she should be able to tolerate a longer A time. my DD's first A time was the shortest until recently.
45 min naps can mean UT so you may actually want to try to keep her up a little longer after a good nap to get her tired enough to take another long nap. kwim?
1.5 hours A time is low for that age, but if it works for her great! good for you for figuring it out!