You said the GC stated that high betas are a marker for Down Syndrome. That statement is only true based on when
the hCG is measured. In other words, high betas are relevant only when measured in that latter part of the 1st tri when you enter the window for doing a triple screen. Even then it's not matter of hitting a specific hCG number, (i.e. if you have a beta of 75,000 that means you have a marker for DS). There's some calculation done, specifically Multiples of Median (MoM)
I'm only making a point of clarifying this because I don't want ladies to think that if they get a "high" (which is a very subjective term) beta at 14DPO that that means they have a marker for Trisomy 21. If that were the case there would be plenty of women with need to worry.
To reiterate what everyone else has said, focus on the fact that there is a far greater chance that everything is perfect. You really do have good numbers. And do not make a correlation between your odds for Trisomy 21 and the odds for Trisomy 13 and 18. Again, allow yourself to focus on the positive.
Btw, I think it's great that you're doing this maternit21 test. But even if you didn't have that option, there's the SequentialScreen. This is what I did. The advantage is you can test as early as 10 weeks - although I waited until I believe it was 11W6D or something like on the advice of my Genzyme GC.