Hi mama! Sa 2 months, okay na usually to introduce the bottle kaya baby gets used to it before you go back to work or need a break, a few of us tried around this age and it helped na hindi na-struggle ang babies later. For storing, room temperature is okay for a few hours (usually 4 hours), pero sa fridge talaga mas safe, you can keep it there for up to 3-5 days, pwede sya hindi sa freezer if you're using it within that time, pero if you want longer storage, freezer na talaga (up to 6 months). Best approach is to ask your pediatrician kung exactly how long and kung best storage setup para sa routine mo, kasi depends din on your situation!