Hi mummy, you don't need to straight away give your girl stage 2 formula milk 🧐. Start by mixing the milk with stage 1 and 2 (e.g 2 scoops of stage 1 combine with 1 scoop of stage 2, when she is comfortable with this, you can slowly follow by 1 scoop of stage 1 combine with 2 scoops of stage 2 etc.) That is how I transit with my lo's formula milk stages.
You can stay with stage 1 all the way as it's nutritionally the most similar to breast milk and also better regulated. Stage 2 onwards may have more added sugar.
Zen zen