Anti tetanus

Hi mommies, I just had my anti tetabus shot yesterday administered by my obgyn. I asked her if how may shots should I take since a lot of mommies here posted they had 2x for 1st time pregnancy and 1x for succeeding pregnancies. However my obgyn said I only needed 1x shot. Im a #1stimemom and this pregnancy is my #firstbaby at 28weeks & 6days and as far as I could remember the last anti tetanus shot I had was more than 20yrs ago ( when I was a child) 😂. I am A lil bit of confused about this matter. I wasnt able to ask my ob that time since I am preoccupied of other questions to ask. 😅#advicepls thanks in advance.