Is 33 weeks too soon?

I have been told you can start Evening Primerose Oil as soon as 28 weeks or at the beginning of your 3rd trimester but also heard you can't until 36 weeks. I don't want to go over my due date again and don't want to be induced! What week did you start EPO, how many a day did you take, and do you think it helped labor either by just making it a smooth delivery or do you think it helped soften you cervix and dilate you. I don't want to deliver too early but I don't want induced either 😟