I think what you are doing sounds wonderful, because it is working for both you and bub!

With my first, I co-slept with him most nights (or partial nights) on and off until he was about 3.5, but was too afraid to start until he was a bit bigger, I think he was a couple of months old before I started bringing him into our bed.

However this time around, with Eva, she has been sleeping next to me from the moment we came home. I actually have had her cot set up next to our bed, with the side rail off so it is basically a sidecar extension to our bed (and both the cot and bed mattress are the exact same level). I am only inches from her, but know I wont roll on her because she is in her own space.
It really makes things like feeding, & putting in dummies, etc, so much easier I find. and I sleep SO MUCH better with her right there.
I remember with Aidyn, he was sleeping in another room in those first weeks, and I was constantly plagued with anxiety, and restless sleep, because I was always listening out for him.

There are a couple of great articles HERE and HERE which explore some interesting facts and benefits of co-sleeping. Maybe you could print them out and show them to your mother and MIL to help them to understand just how beneficial, and safe it can be?