Oil on Vagina during Pregnancy

So I’m in my first trimester and I’ve heard from someone who swears if you start putting a little olive oil on you vag and down almost to your butt through the whole pregnancy it keeps it super moist and elastic and then reduces the chance of you tearing. Tearing is my only fear of birth. Is this okay to do? Would the oils be bad idk lol. Is olive oil okay or another oil better or any other advice to prep for labour