I didn't have one that early either 18 dpo though mine was 2231 and I got my ++ at 3 weeks 4 days. I wouldn't really worry about 1 number though as there is a wide range of normal. Just as long as its doubling like it should then I wouldn't worry.
I didn't get my HCG done at 3 weeks, but got a bright sportive at 3 weeks 5 days. I am now 8 weeks 3 days. My last HCG was 6 weeks 1 day and 24,401