I am so intrusted in one of these bags, I was wondering if anyone has the london? I am thinking about getting it but I am unsure because Tucker is 7 pounds, and I want enough room for our newest edition when she arrives

she will not be big as tucker but unsure of he size seeing she is nine days old now. ( just thinking ahead and I dont want to plan on carrying around two bags ) Any feedback is appreciated and if anyone has this issue what bag and size do you have?