Thanks for the query.
Ideal size of follicle during ovulation is 19mm-23mm.
But let me also tell you that follicle increases by 1-2mm every day, so just relax and let your Doc have you on follicular monitoring for few more days.
Ovulation usually occurs between 14th to 20th day.
Continue taking folic acid
, Eat healthy, reduce weight if you are overweight
, exercise regularly.
Stay hopeful..... All the best!