i have been where you are.
they are supposed to start to level out around 7-8 weeks or at least stop increasing, so if they do that, you are really not that far off the top end of the scale(bb guide 7 - 12w: 11,500 - 289,000) but remember these are a guide only. I was 26 and at the 10wk bt my hcg was 1million, from memory my afp level was very low too this made me high risk, nt scan showed a perfect baby but still only lowered my risk to 1:82. I had an amnio and there was/is nothing wrong with dd, she is a perfect healthy toddler now. while it is something they use as a marker, its just one of several factors. if your hcg starts to drop, by the 10wk bt it could be in the guide range and you will have worried about nothing. Please dont stress yourself out when you dont know if theres anything to worry about anyway. i have had 2 bt's this time and had high levels both times again so its at the back of my mind too, but i made a decision not to stress myself unless i have to, easier said than done i know, but even if they tell you you're high risk, that doesnt necessarily mean theres anything wrong and so often we are put through this stress for no reason. hugs hun, let us know how you go. hth