To disclose a past abortion to a new partner or not?

Short story is that I had an abortion at 18 (please don't judge). The father and I broke up a couple years later. I've now met someone new and we are not dating yet but we are prob going to soon. We are still getting to know each other. Should I disclose my abortion or keep it to myself? If I should disclose it, when should I (now, once we start dating, if we get married, etc) ?!?!?