Hey Kenji Quacker Sounds like you are going about things with a good plan, and proving your sense of responsibility. Proud that you would take on the expenses as well as the chores.
Fostering might be a great solution for a dog. That way you could potentially meet different breeds, sizes, and needs.
We also have doggy home-stay day-care here. So if I have be be away, my dog is staying in a family home with people I trust. Could be just overnight, weekend, whatever. Maybe your Mom would consider that.