2.5m old has active tongue(sticks it out a lot, smacks) and is starting to have trouble first taking a bottle (bf and bottlefed) gags often. normal?

Maybe: Most 2.5 months old have active tongues, so that part is not concerning. Need more information, was baby eating fine prior to this, not having trouble sucking> just gagging later? Most of what you say sounds kinda normal but would need more information. :)

Could be normal: Is baby spitting up/arching or uncomfortable? What you are describing could be normal but I would want your baby's doctor to know about it and evaluate it. It's most likely nothing,could be reflux but I would want to make sure smacking is not seizure activity.