When I told my parents a few years back, I had done very elaborate preparations for Mabon; I cooked the entire day's meals from scratch (went through around 40 apples that day), did crafts, set up activities for the family to participate in, and did a presentation about it. At the end of all of this, I told them that I was a witch who followed an eclectic path.
My family didn't comment. Rather they acted like I had never made the remark and proceeded to praise me on the Carmel apples (as I had made them Carmel apples to eat as I told them). It was surprising the extents they have gone through to erase it from their minds. Even now, several years after, we have only talked about it twice.
I would say that I had a pretty good experience in comparison to what can happen. My family was passive, but many families can also be aggressive, or supportive. I've heard experiences ranging from getting removed from the family, to family members converting over.
All in all, I would recommend that you asses your situation and see if it would be right. You really should not force it, as that will almost always end in a way you don't desire. Try "testing the waters" so to speak. Try to get a conversation started about what your parents think and know about modern magical practices, and if they are accepting of them. Perhaps you could even bring up the fairly recent "Fox news" issue and see what their thoughts are on the matter. (The video link is provided below). Either way, this site offers some helpful pamphlets you could print out and give to them, so they don't have any misconceptions of your practices:
To know, to will, to dare, and to be silent. Those are the four rules of the magi. I follow them and it works pretty well for me. I would advise you to keep them, but if you feel it wise to tell someone of your craft then i wish the best. Your parents will most likely react with disbelief, they probably wouldnt think you were series i would suggest telling them about your practice and explain it in a way they could connect with. It really depends on how your parents are. If they are christian then trytalking to them about the three wisemen and how they were magi. Talk to them about king solomon. If they are scientific and logical then explain it to them as a form of science. Talk to them abouut the works of parapsycologist, Dr. William Reich, Mr. Hieronymus, ect. Hopefully they will accept you beliefs, worse case senerio is they go crazy and through away all of your stuff on the subject, and have you talk to your pasture. In my opinion you should keep it secret.
I am a parent. It would seem more adult to say you've explored religions and find Wicca to be more suited to your philosophy of life. It is very creative, more interactive and that you are more fulfilled in its practices. Blessed be!