Taking three year old to hospital when is brother is born?

So I want to have my three year old son in the delivery room with me, my husband and my sister. Has anyone had any experience with this and have any suggestions about how to go about it? I think it would be a great way for them to be close and for my son to realize what's going on and learn. He is pretty well behaved and my midwife said it was fine and she has had people bring their toddlers before and the hospital is okay with it so that's not a big deal but did anyone regret taking their young children or was it a good experience ? My last labor with my son was 3.5 hours so I'm sure it shouldn't be too long since your second delivery is usually shorter. I'm hoping everything goes well.