My Scottish family database has more than 12 thousand people in in, but no known connections to any Clan. Practically all the modern clan societies are based in the USA, where the enthusiasm for Scottish cultural history is greatest.
If you ask any Scotsman (in Scotland) what Clan he belonged to, he most likely would have no answer at all: the concept being a strange one today.
Finally, most of the population of Scotland has never been part of the clan system, and the National Museum of Antiquities of Scotland catalogue which I am looking at says "There is little evidence about Highland dress and the use of distinctive tartans by the clans until the 17th century, and even then it is conflicting. No tartans in the museum are older than the 18th century"
From the above, you might understand why we in Scotland regard the modern Clans more with amusement than anything else. If it appeals to you, by all means join a clan society - they will welcome you with open arms.