Maid of honour with a new born.

I have a 2 year old daughter and I'm expecting baby number 2 in January, my cousin is getting married next May which I'll be the maid of honour. She wants me to organise the hen do for at least 30 people, I understand that maid of honour's do that but the circumstances have changed. The night before the wedding the bride and bridesmaids and me are staying in a hotel so she wants me to leave my 2 year old with the father but bring her to the hotel in the morning as she is the flower girl ( the hotel is an hour's drive) By may I will have a 3 month old baby so I'm not comfortable leaving my newborn behind and my daughter for the night. My cousin has been messaging me to give her an answer about the hotel if I'm staying because she needs to book it asap but i am not sure what to do, she also said before that she really hopes I'm still going to be the maid of honour. I know she's not intentionally trying to make me feel guilty but I don't think she's thinking about people with kids ect. I just don't know what to do. Any advice?