No "still believe" about it for me even by age 5, and by age 7 I was well over them all; Santa, Saint Nick, the Easter Bunny and the rest of the lot.  I think the last year when I still genuinely believed, or very much wanted to believe, in Santa Claus and in presents being brought by him and by "the Christ-child" (as childhood lore has it in Germany) was at age 4.  At some point after that, I'm fairly even before Christmas at age 5, I had wised up to the fact that the giver of my Christmas presents was really my mom -- and ditto the Easter Bunny (whose existence had really never made sense to me to begin with ... a bunny laying eggs?!).  So when my mom sat me down one day after I'd started elementary school for a "you're a big girl now, so I'm going to have to tell you something because I think you'll now be able to understand this" talk she had obviously prepared very carefully, I just looked at her and blurted out, equally to her puzzlement and relief: "Oh, I haven't believed in that for a long time anyway .."

All of which doesn't mean in the least, however, that I wasn't easily fooled as a kid, especially if I really wanted to believe in something -- and particularly so, by my two elder cousins (the daughters of my mom's elder sister, with whom we spent a lot of vacation and other time when I was little). 

Some of the things they came up with, I just went along with and pretended, simply because I'd have found it much more annoying to have to discuss the whole thing: E.g., while I didn't like the stuff that Germans call Quark (any attempt at translation, e.g., as "curd" or "cottage cheese", is doomed to utter failure -- it's manifestly NOT the same thing), I very much liked cherry compote and preserve, so for a while they tried to get me to eat Quark and cherry compote, calling it "cherry ice cream" and telling me that unfortunately the freezer had failed to work properly ... all of which I wasn't fooled by for a second, but hey, anything for extra stuff with cherries in it (even Quark) -- and if pretending to go along with their story meant I didn't have to discuss that no, I still really didn't like Quark as such, but I did very much like it with compoted or preserved cherries in it, thank you very much, then that was just fine by me.

BUT the one thing they produced and which downright drove me to distraction were Pumuckl's footprints!  Pumuckl is the hero of a series of German children's books; a little kobold / gnome who one day takes residence in a master carpenter's shop, where he instantly proceeds to cause all sorts of havoc.  I used to love those books, as well as the TV series based on them (with Pumuckl's voice done by Hans Clarin), so imagine my surprise when, one day while we were vacationing on the North Sea coast, my cousins suddenly pointed out to me that Pumuckl had to have been around, because look, there were his footprints!  And they were all correct, too, with a big toe print and only three smaller toe prints (since Pumuckl only had four toes -- and he was always walking barefoot).  And of course, shortly thereafter small things started to happen -- my bath towel or my little scoop or something else would disappear and reappear somewhere else entirely; just the sort of tricks and practical jokes that Pumuckl was known to play.  Since as a rule he was invisible, and since I very much wanted him to exist (even though deep down I knew he didn't), for a while I was seriously thrown, all the more since I couldn't figure out how my cousins, or anybody in league with them for that matter, had produced the magical footprints.  So this went on for quite a while, with me skeptical but very much wanting to believe, and my cousins producing more and more evidence of Pumuckl's existence ... until I finally found out how they'd created his "footprints" (namely, by pressing the undersides of their fists into the sand for the main foot impression and then using their fingers for the toe imprints), at which time of course the game was up.  I still think of this whenever I'm on the beach, though -- and whenever I see one of the Pumuckl books somewhere, or come across a rerun of the TV series.

(On the beach in Spain, with my elder cousins (left and center),
a year or two before the appearance of "Pumuckl's footprints")