If I missed it, I am sorry, but how long have had him? If you just had your first feed on 4-21-25, then feed him every 10-14 days for 3-4 consecutive feedings of whatever he was and is happily eating.
Once he is established and doing great with eating then I would switch to weaned rats every two weeks. When growing I would aim for 7-10% of body weight +/- every 2 weeks or so if that schedule works for you. Weaned rats fall right into that weight range. Do not feed a prey item bigger than the width of your snake. Always better to go a little smaller than bigger.
I would get him on rats when you can because as he grows he will need bigger meals than mice can offer. Easier to switch now.