
Hi and congrats on getting a Frenchie! :D
When mine were pups, I always used the 5 minutes per month rule which meant a 15 minute walk around the block - at times they would step in front of me and ask to be carried for a while but after a week they were happily trotting the whole block. Once they were a little older we progressed to 2 blocks - we called them the long walk and the short walk! ;) As well as the pavement walking, we would take them to woods, fields, shopping, anywhere there were people and dogs.
When fit, Frenchies can walk far more than just a mile ( there are even a few who do agility!) - just remember to build up gradually and watch the weather too. Never walk them in the heat of the day, so early mornings/late evenings are better in summer - have you felt the heat of a pavement in summer? Very cold weather can sometimes affect their breathing too so be careful. Heat is a very big worry for Frenchie owners and sometimes you may have to use a fan and a wet towel to cool your frenchie.
Most Frenchie owners I know, use a harness for walking ( I use puppia ones but there are many others and lovely leather ones too) - less pressure on their delicate trachea - collars can cause coughing and gagging especially if they pull! If Mable starts to gag often on a walk and spit up lots of saliva - get your vet to check for elongated soft palate.
Owning a frenchie is a laugh a minute, you will have lots of fun with your girl :)