Yes, unmarried girls can wear payal.
According to existing customs, wearing a payal is not restricted to married women only. Payal is considered the first piece of jewelry a girl receives from her parents, usually at birth. Additionally, according to the reference, "A payal is a sign of bravery and pride in both, unmarried and married women." Therefore, both married and unmarried women can wear payal as a symbol of pride and bravery.