personally I think if you go to a professional place then it's just as accurate as the 18-20 week scan. You can tell a baby's gender from 15 weeks, I went for a gender scan at a private place at 16 weeks 1 day and got told we're having a baby girl. She was in the perfect position and I could see myself clearly they were definitely girls parts haha.
Two other people in my family both paid for scans at 16 weeks 1 day too, 1 was told she was having a boy and she's just given birth to her boy a few weeks ago. The other got told she was having a girl and she's expecting a girl :)
So from my personal experience and people in my family it's always been accurate but obviously just double check at the 20 week scan too!
Go for it :)
I say it's best to wait til 20 week scan:)
Well, we were told we were having a boy at 16 weeks.. at our anatomy scan (21 weeks) it turned out to be a girl