This is Dondorf's number 25 Kinder Spielkarten set, which has children as the face cards. I've been trying to get a pack for years, but they're normally quite pricey as they attract a wide range of interest, not just that of playing card collectors. This explains why the ones I managed to get are wash-your-hands-after-touching-them quality: if they weren't, I wouldn't have been able to afford them. As it was, I got them quite cheap (something like £11 instead of the usual £40+).
How old are they? Well this particular variant was manufactured 1880-1910, but the company added a GmbH to its name in 1906 that my deck doesn't have, so it's from between 1880 and 1905.
If I were that old, I'd probably be pretty grubby, too.