'Program stuck in while loop even though it seems correct

For some reason this gets stuck in a while loop at where it first asks for an input in "userChoice", anyone have a solution?

userStart = input("\n Enter UBM? \n (Yes) \n (No)")
while userStart == "Yes":
    p1 = bank(1234, "Bank Bill", "dragon123", 300)
    p2 = bank(1235, "Billy Jones", "cookies1231", 300)
    p3 = bank(1236, "Johnny Test", "beans100", 300)

    userChoice = input("\n You arrive at UBM; The United Bank of MONEY. What account would you like to access? \n (Bank Bill) \n (Billy Jones) \n (Johnny Test) \n ")
    if userChoice == "Bank Bill":
        p1.passCheck()
        userStart = input("\n Stay in UBM? \n (Yes) \n (No)")
    elif userChoice == "Billy Jones":
        p2.passCheck()
        userStart = input("\n Stay in UBM? \n (Yes) \n (No)")
    elif userChoice == "Johnny Test":
        p3.passCheck()
        userStart = input("\n Stay in UBM? \n (Yes) \n (No)")
if userStart == "No":
    print("You left UBM.")


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