It's not early concept artwork, this is from Character Material a relatively recent publication (meaning way post-Melty Blood). I think Takeuchi said "hey, I wonder how she'll look as a grown up" and here you have it.
Oh, I see. I was wondering, 'cause in Tsukihime, the only mention of her says something about middle school. That, and there was all that business with Tatari, so it's hard to tell.