I'd say you are very close to the end! I think it's fine to wait until August to book your appointment. The only obstacle I can see is if your police certificate expires around that time, but they are good for 2 years.
Here's my DS-5535 timeline for reference:
Oct 4, 2022 Interview for K-1 Fiance Visa - Consulate assured me I was approved and kept my passport.
Oct 5, 2022 DS-5535 email received. CEAC Status 'Refused'. DS-5535 completed and sent Oct 7, 2022.
Nov 2022 Requested passport back from consulate for holiday travel and renewal.
Mar 21, 2023 Consulate email request for new medical and passport. (No WOM filed.)
Apr 17, 2023 Consulate received medical and passport.
Apr 19, 2023 CEAC Status 'Approved' !
Apr 25, 2023 CEAC Status 'Issued' !! Purolator link email received.
April 27, 2023 Visa in hand !!!