1st clomid cycle

J

I started clomid 50mg cycle day 3-7. I usually ovulate on my own around cycle day 20-21. I have longer cycles 33-34 sometimes 35 days. I went in today for ultra sound cd14, largest one she found was 10.85mm. She said don’t be discouraged and wants me to come back in 2 days to check again ? Is it possible for my follies to grow in 2 days ? Atleast to 15mm?