For those that have 29/30 day cycles

What day do you generally O on?? I just got my cycle back 3 months ago because I'm stil night nursin our 17 month son... I had been O'ing about CD20/21 and I just got Positive OPK and O pains this morning at CD18!!! I'm so excited that my luteal phase is lengthening... So this would make me have an 11/12 lp.... Anyone gotten of with that length of lp?