cervical cerclage question

Just wanted to get some advice for later during this pregnancy, i have had 3 babies born early, 35 weeks, 30 weeks and 32 weeks, during my last pregnancy they mentioned they wouldve given me a cervical cerclage if i had started my dr appointments earlier in the pg but im a bit worried about this and if its nesassary, i dont think its cervical incompetents that makes them come early, i was having regular scans for the last one and even a couple hours before hand it was at almost 3 cm, i also have fast labours, my 30 weeker was born in 20 min and with the last baby i was 7cm in aprox. 10 min but she was footling breech so was emerg csec, im just worried it will do more damage than good getting this done especially with my fast labours.

hoping for lots of advice

thanks