When should I test?

Rachel

So this is my first cycle off of birth control. I stopped the pill on the 25th. I had my withdrawal bleed from the 26th-28th. I started using OPK immediately after bleeding stopped. Got my positive on the 30th. Currently 7DPO so when can I test? I know I should wait for a missed period but I honestly dont know when it would be due. Thank you!