Adoption is the natural start of her weight history, but the first entries should not be yours. The shelter weighed her during her stay, often more than once, and those dated figures are a baseline you can never recreate later. Claiming them now gives her history a beginning that reaches back before she came home.
Build the Baseline From the Shelter's Recorded Weights
Request her shelter record and copy every recorded weight into a running, dated record of her weights, with every home entry that follows weighed on identical scales under identical conditions, so anyone can see at a glance which way the trend runs. Write each shelter entry with its date, and mark the entry clearly as a shelter weighing, because shelter scales and shelter conditions are the shelter's method, not yet yours.
If the shelter holds only one weight, start with that single entry and say so. A short honest baseline beats a padded one, and her vet would rather see one true figure than a reconstructed series. Ask also whether she gained, lost, or held steady during her stay if the staff recorded it, and note the answer as an observation beside the figures rather than as extra figures.
Fix Your Own Method and Never Change It Quietly
From her first home weighing onward, pick one method and keep it: the same scales, on the same hard floor, at the same point in her day, and ideally before a meal rather than after one. Write the method at the top of the list in plain words, so anyone continuing the list later can copy it exactly instead of inventing a close version.
Weigh her in the carrier and subtract the carrier, or step on the scales holding her and subtract yourself; either approach works, provided it is the approach every time. If you ever have to change scales, note the change beside that entry and weigh her both ways once if she tolerates it, so the join between the two series stays visible and honest.
Weigh her on a gentle rhythm once she is home rather than constantly: a weekly entry while she settles, then a steadier interval once her eating and routine are established, always her usual way. Frequent handling for the scales can unsettle a newly adopted cat, and a frightened weighing is often an inaccurate one because she will not sit still on the platform. Read single entries with suspicion and runs of entries with confidence. One odd figure usually means a wriggling cat, a moved scale, or a full stomach; three entries drifting the same way usually mean the trend is real and worth raising.
Read the Trend, and Let the Vet Judge the Number
The list exists to show direction: steady, creeping up, or slipping down across weeks and months. It does not exist for you to set a goal figure for her, because a healthy weight for her frame, age, and history is a judgment for her vet, who can feel her body condition in a way a scales reading never captures.
Take the list to her first check with your own vet and whenever the direction changes without an obvious reason, such as a new home or a new food settling in. A weight concern raised early, with a clean dated list behind it, is a far easier conversation than one raised from memory. Her shelter-started list lives inside Pet Passport as a dated series, and KinsLe keeps that series growing in the same style from her first entry onward.