Hi Ashley, I suppose it depends on several factors. First and foremost, is this interest (that you don't want to share with others because they may criticize you for it if you do) something that you know that God wants you to share with them? If so, then yes, continuing to hide it from others in that case would most likely be a sin.
Or two, could not sharing this interest of yours with others be somehow detrimental to their well-being in either the short or the long-run? That could also be a sin.
Or perhaps three, could not sharing this thing impugn your character or your Christian witness with the very people you are hiding the truth from (or others) if they ended up discovering what you were doing? (I'm not sure this last one would necessarily be considered a sin, but do you really want to hide what you know from them if your character or witness might be brought into question because of it?)
It would help to know what you are trying to hide from others, but you should not share that here unless you feel comfortable doing so.
One last thing, do you think God is ok with you hiding this particular interest of yours from others, or do you think He would He be displeased with you for doing so?
Yours and His,
David
2 Timothy 3
12 All who desire to live godly in Christ Jesus will be persecuted.
.