Cactus flowers tend to only last for about a day. Some can last for a week or two but typically their flowers are short-lived

I’m going to add to what Emily has said. What can also happen is if the flowers don’t get enough light they wont open all the way.

The plant is otherwise in good shape. It could be potted in a slightly bigger pot to let the pups grow. It looks like a Gymnocalycium.

Yes, it's Gymnocalcium.

Thank you all for the replies! :) I am really new to this so I was really worried about the flowers.

Thank you all again :)