Ok to TTC or... nah?

My first born is almost 14 months. I’d like to TTC soon for #2. But I’ve only been taking my prenantals for a few days?

Don’t you have to take the prenantals for three months before ttc?

I had infertility before but I have many signs that my fertility has greatly improved (had a lot of lifestyle changes).... so I’d like to ttc soon

But what about the prenantals?