When to test after clomid ?!?

So today I am 8dpo and having some cramping since yesterday. Today I went out and bought 2 first response test to have and test when I am 12dpo!..is this a good time to test since i don't know when my af will come? I took clomid but I'm also irregular and usually a 45-53 day cycle,but I've heard that clomid sometimes makes it come sooner..I really don't know!! Is 12 dpo a good time to take a test? Please any insight thanks!