I also waited until my 18-20 week scan for both of my pregnancies. I didn't have the dating scan before the 8 weeks as I knew I was pregnant and approx how far along as my period is very predictable.

I also chose not to have the 12 week scan as I was not going to abort the baby if s/he had any abnormalities (i.e. Down Syndrome etc) unless they were so incredibly severe that they were "incompatible with life" which should show up at the 18 week scan. I just couldn't do it and I knew myself well enough to know that. I also did not want to go through the stress at such a precious time as I knew the 12 week scans can be very inaccurate. TBH, I didn't even ask my DH's opinion about whether he agreed (which thankfully he did when I explained my reasoning).

If you are happy with your decision, then it doesn't matter what others say/think. I believe I made the right choice for ME.

Enjoy the rest of your pregnancy!