6 minutes of this video that will save you a lot of trouble in future.
Yes, crochet circles are tricky, but if you know these rules, your circles will be perfectly round and flat, if you use Single Crochet, Half Double Crochet or Double Crochet stitches (US terms).

PDF file is available here:
https://crochettanya.com/crochet-stitches

YT video is here:
https://youtu.be/apT75d275D0