Gonna start trying for our first soon

My husband and I are both mid thirties. We're planning on starting to try for our first child this summer. I was recently told that my uterine wall was a bit thick (16mm at ovulation). My doctor seemed a bit concerned and asked me to make another appointment immediately after my next period. She also told me to start prenatal vitamins. Anyone go through a similar situation? I've read that drinking apple cider vinegar is a natural way of regulating hormones and possibly helping the thick wall situation. Any feedback would be appreciated.