Teat bottle

Is anyone else baby struggling to change teat size. I did stop breastfeeding last month and she’s now about to be 7 month and my LG is still one level one teat. I did buy the Philips glass bottle but only came with 3 teat. Do you think I should buy the 2 level first? Also she only ever drinks half and finishes the rest later is that because she’s tired of sucking. Poor baby I feel bad but I only had level 1 because I was breastfeeding now I feel like she doesn’t drink as much milk. 😔