Hi Learner27,
By the middle/end of your PhD you should be a world expert in your very specialised field, so you will often find that you know more than your supervisor at this point. At the start of the PhD, as long as your supervisor is supportive and knows enough about your topic to objectively look through/check draft lit reviews etc. I'd say it is fine. Maybe ask your supervisor's opinion- does he/she think they are OK with your project direction? Your supervisor will want you to pass, a fail looks bad on them.