Hi! Congratulations on your LO!
I have an LO who was 9 weeks early. Now she is 9 months, 7 months adjusted. I have always based her EASY on her adjusted age and it has worked fabulously until just recently. Now, as I think she's starting to catch up, I am using somewhere between actual and adjusted. So I'd suggest starting with her adjusted age since she's so young.
HTH
Good luck!