cannot remember when my son learnt to hold his milk bottle. I guess is around 6-8mths that time.
For upright position, I think around 11mths or so.
You can start training your child to drink from straw as early as 12months. As long as he/she knows how to drink from spout bottle, it's quite easy to train to drink from straw.
Sometimes it's a habit the child doesnt want to hold the bottle not that he/she doesnt know. Lazy maybe..heehee