Hm. My general rule is that a month after the birth I am much more likely to be able to get on with the more usual socialising (as in not just letting people in for a newborn cuddle whilst I try to stay awake 
), as I’ll be starting to feel a bit more normal in terms of healing and getting into some sort of rough routine. However recognising I would still be tired and caring for a very small baby and wanting to keep things quite simple.
The tricky thing here is, you don’t know when you’ll actually go into labour. It’s common to go overdue, especially with first babies, so you could likely be only one or two weeks post partum at the time of the wedding. In my mind that feels too soon. You also don’t know how you’ll feel after the birth. With my first the labour was fairly straightforward although a long pushing stage, overall I thought I was fine, and then promptly spent about two weeks in bed following an infection and being put on heavy painkillers and ABs, then needed a few days/a week to get back to doing things. Nothing unusual or extreme happened, I just happened to get an infection a few days after birth. A month after the birth however and I was out and about doing different things.
Bear in mind it’s not just about tiredness and a newborn. Your body is healing. It’s gone through a major event. You could still be shedding lochia, your muscles will likely still feel a bit weird, there might still be some tenderness, or secondary issues like piles. If you’re breastfeeding you might still be getting used to feeding, your supply, leaking etc.
You just don’t know until the baby is here, however my personal opinion (and I appreciate not everyone would agree) is that women should give themselves at least two weeks of rest (as in, no major engagements, going at your own pace, taking it easy, just doing the essentials), letting the body heal as much as possible whilst getting on with adapting to life with their new baby and bonding.