Bridal Party Advice

This is a long problem but please stick with me.

My brother and his girlfriend got engaged last week and were planning on a 2018 wedding. My husband has been asked to be the Best Man, I have been asked to be a Bridesmaid and bump has been asked to be Page Boy/Flower Girl. The wedding - due to her Grandma's health - is now in 6 months time so here in lies my problem. Bump will be, at the most, 8 weeks old by then so I feel like maybe I should not be in the Bridal Party in order to allow me to see to the baby and not detract from the bride and groom. I will help them as much as I can but do you think it is OK to explain that, as I can't give the bride 100% of my attention, I don't feel it is fair on her for me to be in the Bridal Party. I also don't think I'll be able to go to the Hen Party as I'll either be very pregnant or have a new born and I hope to breast feed.

This is our first child so I don't know if I'm being over cautious or not so would really appreciate any advice please.

What I don't want to do is hurt anyone!

Thanks in advance :)