I really do not like my original shirt choice. Is there any way I can switch clothes without deleting my character?
Not sure currently, but if you notice, there are clothing/armor? slots when you open the inventory. Will let you know if possible as I get further in game.
One of the townspeople told me that you need wool to make clothes and a loom, providing you have the recipes. I think it was Evelyn. But i'm not very far in the game.
On reddit there was a post today its a minor spoiler since it is initially locked https://www.reddit.com/r/StardewValley/comments/48ixas/how_to_change_character_appearance/
befriend the wizard to 3+ hearts and enter his basement. pay 500G to change your clothes, skin color, hair style, etc
Someone told me once you get Wizard to 5 hearts you can edit your clothes somewhere in his tower. I don't actually know if it works because I haven't gotten him to that many hearts yet.
It's already been said but once you get your friendship with the Wizard high enough you will get access to the cellar. Go through his house and there is a trapdoor between the book shelves. If you try to access it too soon, he will say, "what are you doing I only let close friends in there" or words to that effect. Once in the cellar the changer is on the right and it will ask for 500G and then you get the same screen that you did on start. I do this often so that her outfit changes with the season. I really wish that there was a dresser where the outfits could stay so you don't have to keep paying each time.
There's a couple of mods that give you the ability to change in your house for free. Get Dressed is one, the other comes with the Bathroom After Second House Upgrade. If you don't mind modding to get what you want.