Is it wrong to not invite her?

My friend is 32 and has 4 kids. Recently she just had her 4th he is one month old. Our friend group wants to have an outdoor bbq now that is nice outside and we would social distance etc. It’s about 5 of us. We are on the fence about inviting her because she just had the baby and has 3 other kids and one time that we invited her she told us she didn’t want to hang out with a bunch of 18yr olds (the rest of the group is 18-25 with no kids). Do you think she’ll get offended if we don’t invite her and she finds out we had the bbq?