Hello
@Newbie2021
Your daisy looks like it's growing fine. However the browning leaves could either be two things. Over watering, or too much heat.
How much water do you give your daisy??? And has there been an increase in temperature lately, causing the leaves to brown???
Dead heading the shriveling blooms will also help with the plant's energy to produce more flowers, instead of wasting it on forming seed pods. Unless you want to save your daisy's seeds.