I had a mild triple prolapse with dd (crappy conective tissue, love my genetics). No one suggested a cs for my second dd's birth. Generally prolapse happens during pregnancy not during labour therfore I cant see how a vaginal delivery could make it worse or why you would need a cs. I would get a second opinion. Speak to your midwie or see a gynae or obstertrician.

I saw a pelvic floor physiotherapist after dd1 and she did wonders for my pelvic floor, I really urge you to see one it made such a difference. Unortunately as we age damage to the pelvic floor becomes more noticable so improving the strength of your pf now will help later. My pelvic floor is better ater my second pregnancy compared to after the first. There are private pf physios and I know my local public hospital has one, get your gp to write a referral. Good luck