You should see a difference on a stimulant ADHD medication immediately, and know how you will do on it overall within a few days.
There are many different stimulants to try and even two different types: amphetamines and methylphenidates. Most people do better on one type or the other, but not both.
Female hormones do affect ADHD as well.
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism