It's a question that I often wrestle with as a blind person and trust me when I tell you that as a rule, blind persons are often faced with this dilemma. Speak up too strongly and society may misunderstand our reasons and they may even be uncomfortable with us. Not speak up and more often than not our feelings are ignored and our rights are inadvertently trampled upon.
I do not believe that there is any right or wrong time to speak up. It all depends on the circumstance and/or situation and why it needs to be done. Speaking up on the whole is not a bad thing by any means, but it needs to be executed precisely and appropriately. It's not what you say, it's how you say it. Keep a hold of your phrases and words and make sure that you are in control of your tone of voice at all times.
I'm Donna J. Jodhan your friendly accessibility advocate wishing you a terrific day.