LH surge CD8?

Rebecca
Hi everyone I'm new. I'm 34, been ttc for almost 10 years. I have grade 3 endometriosis. Used clomid in 2015 and unfortunately had a mmc at 11 weeks. Just started to try again and I'm on CD8 and with clear blue digital I've had LH surge? This isn't normal for me as I'm normally CD11. I have read somewhere that as you get older your ovulating will change. Is there any possibility that the test could be wrong? Thanks