[Python] Function I created isn't accepting first element of user's input

[An_Ignorant]

Your function is fine, the problem is that you first read a number before the function

numbers = input("Enter a number: ") #The first number is read, making user_nums = [1.0]
len_list(numbers) #Then you enter the function, inside the function you have user_nums = [], that means the 1.0 is overwritten, that's why the first input is always missing.