How long can it take to get pregnant?

Varies: Pregnancy in the general population is only 15-20% per month among healthy normal couples under the age of 40. It is 10% if 40y/o or older with a 30-50% miscarriage rate. So infertility is defined as: no pregnancy occurs after one year in normal ovulating couples. So if you are younger it may take up to a year.

~20% per cycle: The ideal time to have sex is 1-2 days prior to ovualtion. Doing so would probably yield ~20% chance of conceiving each cycle, ~50% chance conceiving within 6 months, ~85% conceiving within one year. If not pregnant by then, recommend seek infertility evaluation.

Depends on variables: Many cite an average of 6 months trying before achieving pregnancy.That include some on the earlier and later time frame. After a year or so some would consider a fertility workup on both parents.