How do I make this teenager shirt fit a three-year-old?

My daughter loves Frozen. My husband loves my daughter. He bought her Frozen shirts. My husband is not used to shopping for kids clothes. (And, let's face it, department store clothing areas are not organized in a logical fashion. Why aren't all the shirts that are one size, in one place?!). Anyway, he bought her the wrong size. Pretty sure we can't return it because of coronavirus, and even if we were allowed to, it seems nicer to just try to resize it than to return something that might have germs on it.

But, how do I resize it?

I attached pictures of it compared to a shirt that actually fits her (she's size 3T, but this shirt is 4/5t, because I always buy up as size). The shirt that is too big is size 14/16

An easy way might be to just add a seem across the shoulders taking in the sleeves. Then trying on her to see if that helped.  You might want to baste stitch at first.

If that helped, try the same thing down the sides.

You could just snug up the back with a mitten clip or two, or tie a knot at the hip, and let her wear it as a tunic, or just let her wear it as a nightie, with some comfy bottoms, until she grows into it?

I would make it into a T-shirt dress. Find a coordinating fabric to add length to the soon-to-be-dress. When sewn into a tube, it will need to be 1 1/2 to 2 times as wide as the existing T-shirt is at the hem. Put in your hem to the fabric, now gather the tube to fit the t-shirt and sew the top of the skirt to the bottom of the T-shirt.

Viola!

Except that it will be really loose. Try out those mitten thingies on it now.

Maybe that was as clear as mud. Here is a tutorial. But don't cut anything off the t-shirt. It will be a drop waist dress like below...

Joylynn Hardesty wrote:I would make it into a T-shirt dress. Find a coordinating fabric to add length to the soon-to-be-dress. When sewn into a tube, it will need to be 1 1/2 to 2 times as wide as the existing T-shirt is at the hem. Put in your hem to the fabric, now gather the tube to fit the t-shirt and sew the top of the skirt to the bottom of the T-shirt.

Viola!

Except that it will be really loose. Try out those mitten thingies on it now.

Maybe that was as clear as mud. Here is a tutorial. But don't cut anything off the t-shirt. It will be a drop waist dress like below...

My mom made a ton of these with sweatshirts and flannel, or dressier holiday fabrics, for my & my sister's girls,  when they were little. We all loved them! They were cute, fun, easy to wear & wash!