7DPO When should I test?

Jessica • TTC # 1
I'm 7 DPO today..when should I test? AF is due 04/01. My birthday is 04\02 so I'm thinking of testing the day after missed period and hopefully I will get the best birthday present ever. I have had an increase in creamy CM and have been really tired. I have also had some pinching cramps on my sides.