That is very common in puppies. And since you've only had her for a week, it will definitely take some time. Just keep taking her out for short periods and walk her around in the garden. You can also put the lead on in the house and walk her around there too just to get her used to it.
I have 4 dogs (1 Frenchie and 3 Bulldogs) and I remember all of them as puppies would take awhile before they would actually walk on the lead. It was baby steps and took a bit just to get them down the driveway. My youngest literally wouldn't take 2 steps until she was 6 months old.
Patience and consistency!