As someone who still uses a twelve year old MacBook I've been reluctant to weigh in on this, but FWIW the broad consensus on the net (with which I wholeheartedly agree) seems to be that the 2012-2015 13" and 15" Retina MacBook Pros are still the best laptops Apple ever made (though hopefully that will change soon... ;-).
Sure the new ones are faster (especially their SSDs) but in normal use the difference in speed doesn't come close to outweighing the difference in street price. But all those ports!!! Not to mention a real keyboard and MagSafe, and upgradeable SSD.
Of course it really comes down to intended usage. If she just wants to run SC projects and email and browse the web at the beach then a 12" MacBook or an Air is certainly adequate (and a LOT smaller and lighter). But for something approching the full desktop experience that fits comfortably in a briefcase (without a big bagful of dongles) that generation is the bee's knees (especially the 2015 15" with Radeon R9).
Whether the 13" or 15" is a better fit depends largely on how far she plans to carry it (and along with what else), whether she's doing something that DEMANDS all that extra screen real estate and four cores, whether the goal is to use it on-the-run or just to transport her desktop environment from desk to desk, and (assuming the latter) whether there'll be a big monitor there she can plug it into. There's only a pound difference in weight but the 15 is whopping huge by comparison so despite the small weight delta in practice the 13 will be FAR more luggable. SuperCard likely won't run appreciably faster on either, but for something like editing video while riding the bus the 15 wins hands down.
On the other hand if she's just gonna be taking it out of the closet now and then to run a SuperCard project, I don't suppose all those ports make much difference...
HTH,
-Mark