LOL,
I love that series but got super busy and really didn't watch almost anything for a few years then felt super lost when I had time again
I would just start from the beginning again since you probably won't remember all the details that will make the stuff you haven't watched yet make sense.
Also, you should watch in the correct order if you hadn't already been watching it that way. Anime release order is unintended and makes the story more confusing than it's supposed to be. The blu-ray box sets for Second Season (Japanese and English) and Final Season (Japanese-only release unfortunately) are both in novel order. There is no box set for First Season, but given what they did for the other seasons, you should assume novel order is the way to go when watching that.
Follow the order here:
Guide to the Monogatari Anime
Where, why, and how to watch the (in)famous Monogatari series.
edomonogatari.wordpress.com