Ivf - blastocysts

Has anyone noticed a big drop from fertilisation to blastocyst stage. I had 16 eggs thawed, 12 fertilised, 8 at day 3 and then only one poor quality embryo at day 6? Has anyone else noticed this with <a href="https://glowing.com/glow-fertility-program">ivf</a>. Just worried as it’s our first cycle!