When will my buds become bigger? Will they be dense or airy?

this is mostly determined by genetics and also environmental factors come into play relative to those genetics. Those will fill out. the stigma are still projecting a long way without ripened bract/pistil. The density can be better felt, obviously :P i'd give it a while before you start squeezing the colas everyday, though. lol, don't do that often. don't do it, period, but if you must know. check it out as it is your plant. autos are smaller plants. smaller plants typically have smaller buds.