Hi!
I am currently doing this, son is 2 and he has lived here from birth.
Totally doable and has helped me and my partner save to buy a house.
Saving money is probably the only real positive for me.
Negatives:
Far far too warm in the summer.
Far too cold in the winter.
Lack of storage, never knew how much room toys, boxes for nappies, steriliser, bouncy chairs, jumperoos etc take up.
Thin walls, very thin walls! So noise can be an issue.
50% of the place is windows, so now in summer it's very very hard to get my son to sleep as it is so bright. I would advise investing in Black out blinds / gro blinds if you haven't already.
We don't have a full size bath. Just a tub and a shower over head. Fine for my son, not great for me.
Space really, now I have an active toddler, we really do trip up over each other.
I actually miss stairs!
Stair gates to block rooms are hard to find to fit and the walls are so thin, so large gates that attach to the outside wall have been needed and take up so much more space as opposed to pressure for that fit flush with the door frame and as with being open plan I couldn't risk my son crawling to the cooker when it was on so we really didn't have a choice.
It's not a completely negative story though, the benefits of being in the country and to have low outgoings enabling us to save has been a lifesaver.
Hope you get on well I'm sure you will be just fine!