How far in advance should i bake cupcakes and make the buttercream?

I think either way is OK if you store them in a closed container overnight in the refrigerator.

It's always good to make things ahead especially the day before needed. The buttercream icing will keep the cupcakes fresh.

Cake is always better the next day, so your instincts are right. If you frost them tonight, the icing can get a little crusty (I don't mind that, but some people do). You can make the frosting ahead of time (tonight) and refrigerate it, but remember to bring it back to room temp tomorrow before you start frosting tomorrow, or you could be ripping off some muffin-tops with sugar-cement. Make sure the frosting is tightly sealed/covered overnight so it doesn't pick up any other "aromas" from your fridge. I think frosting them closer to serving time is optimal. I know all the high-end cupcake shops in NYC have an icer spreading away right by the counter, so that must be the secret to a better cupcake.

Hi, I'm not a pastry chef or anything, but I am a mom who bakes a lot and I do it very well. (haha) But yes, that is a perfectly acceptable time limit for fresh cupcakes. If you wait till the last few hours before you start them then that leaves you no time for anything else or any mistakes that might occur. I bake a lot of cakes for my family and friends, and I always make the cake the day before, and then ice and decorate it the next day. I wouldn't make a buttercream frosting the night before, because you need to refrigerate it since it has butter, but then if you do that you will not be able to spread it on the cake. Frosting is best made right before you are ready to frost your cupcakes. So you are on the right track! Good luck!