Boozlebub, I know exactly how you feel about OH's sister, I felt the exact same about mine when she got pregnant with her 2nd baby in 2 years, still under the age of 20. It will be your turn soon!
We went for our 3D scan last night, and it did not go to plan! Little girly decided to have her face down and no amount of jumping and eating sugary foods made her want to move. Of course as soon as we got home she started to move around like crazy. Going for a re-scan tomorrow hoping she decides to co-operate, silly baby! Luckily she's growing well though (and definitely still a girl) so it was still a good scan!