Moving your availability date prior to an actual interview is no big deal. Airlines won’t care and likely won’t notice.
Folks were getting in trouble, or shown the door, for changes AFTER the interview. Basically they got hired and then said, “oh by the way, i really can’t start in February .... how’s August sound?” If they think you’re being dishonest you’re sunk.
Prior to the interview, you can change dates and stuff on your app as you see fit