How long does settling take?

[thescruffiestgiantintown]

DD (2.5) has recently started preschool. She claims to like the staff and the other children but she's getting more and more teary while there (happy enough at drop off so far).

I like the place a lot but it wasn't my first choice, and a space has come up at my first choice (which I think would be a better fit for DD).

I'm feeling very torn about whether I should try current place a bit longer to see whether she does settle or try moving her or even try half the week at one and half the week at the other to see if a clear preference emerges. In short I'm lost! Any thoughts would be much appreciated.