I want to make the Little Baker Oven available for teens to use. I already tried messing around with the objects.package in SimPE (which I probably shouldn't have done, since it wigged out on me) but it made no difference in-game. I know you can make teens act like children using SimPE, but they crouch to fit the height standard and it's just all-around weird. Is it possible to edit the oven to do this, and would I have to fix the animations and stuff too?

There are only child animations available for the oven, so you have the choice of crouching teens or just using a regular stove. And don't mess with the Objects.package file, or you can end up messing up your game.

Kids don't really have much else to do with the stove than making muffins, while teens can use regular stoves and make whatever they want (I think I saw the muffin as a regular food dish somewhere). If you want teens to have proper animations, maybe scale up the toy oven and use a regular stove as a base?

The create section is a better place to ask for help in regards to modding projects.

Sounds like they already DID mess around with the objects.package. Which means they'll need to replace it asap - preferably before trying to do anything else.

And in the future - DON'T DO THAT!! :D

I use this for quick muffins. https://www.modthesims.info/download.php?t=235726

Modifying install files directly is not a good idea. Most mods are made by extracting/cloning the files you want to modify and putting them into a new file in SimPE, editing these the way you want them, and putting the file into your Downloads folder.