Need a cycle buddy

This is my first month trying to conceive with my boyfriend. We have been together almost 4 years now. I already have kids with my ex husband but my boyfriend doesn’t have any yet. I’m a little worried since he’s taking lexapro so I’m not sure if it will make it harder to conceive. I also haven’t been pregnant for 7 years (I’m now 32). My boyfriend said he just wants to let it happen when it does but I’m hoping for sooner than later because my kids ages will already be far apart if we can get pregnant. Normally my cycles are only 26 days long but last month I was late by a week because I was on an antibiotic for 5 days so now glow stretched out my period to being longer than normal. I’m guessing I should probably start my period around the 20th to 22nd.