Stories of "mahou josei" - spins on mahou shoujo featuring the trials and tribulations of older characters - are something one would *think* would be a no-brainer, considering the genre's root inspiration from the supernatural-domestication sitcom Bewitched. In truth, however, I've found examples of anything approximating this concept or theme to be *exceedingly* rare, and ones that do it well rarer still.

The anime that supposedly tackles the prospect most directly would be Oku-sama wa Mahō Shōjo: Bewitched Agnes (a.k.a. My Wife is a Magical Girl: Bewitched Agnes). I even wrote about this one a fair bit here - https://paragraphplague.wordpress.com/2015/01/26/final-diagnosis-my-wife-is-a-magical-girl-and-the-myth-of-mahou-josei/ - but the short version is simply that it...well, isn't really very good by any metric. There's a flame of a genius idea in here about a magical girl having to face the inevitable mundanities of becoming an adult, snuffed out by lackluster direction and milquetoast characters. Still, it's there if you're curious.

Mahou Shoujo Lyrical Nanoha StrikerS is an interesting case study in that it takes the young protagonists of the first two seasons of Nanoha, carries them into the future, and then presents the obstacle of an adopted child for them to protect. That *sounds* great on paper...but unfortunately, StrikerS is a little too interested in simultaneously playing the role of a paint-by-numbers sci-fi-action thriller, and this particular thread goes sadly underdeveloped. Don't expect it to be fleshed out in the follow-up season, ViVid, either, because that show will likely go down as one of the most insipid, directionless, vile pieces of media I'll have consumed in 2015, not just anime.

Honestly, the best take I've seen on "magical moms" and the only one I would recommend without many reservations involves characters who are only in the third grade: Ojamajo Doremi Sharp, the second season of Ojamajo Doremi. In it, young girls are tasked with the care of an infant, and both parties have access to magic powers. Ojamajo Doremi was and is already a heavily "family oriented" show, but Sharp goes so far as to make it the foremost thematic vertebrae in its body. It handles the subject of child-rearing and motherhood with extreme maturity - even darkness at times - and its ending pertaining to such is nothing short of triumphant. It can rough-around-the-edges at other points, but Ojamajo Doremi overall is a fantastic little program with more to say and emote in single episodes than most kid's shows have in their entire existence, so I'd highly suggest checking it out.

I think any other examples I could care to name would be stretching the question a bit (e.g. Fresh Precure on the sole basis that one of the mascots is infant-like), so that's about as far as my current knowledge extends on the subject. Hope this was helpful in some way! If I find additional exemplar in the future, I'm sure I'll be very noisy about it and *someone* will hear!