Using classes vs. using functions

I am trying to learn how to tell if my code will be better off creating a class as opposed to using many functions. I am a new Python programmer trying to get the hang of when classes should be implemented.

Determines whether the username is valid or invalid:

def is_good_user(user):
    is_user_good = True
    if user in database:
        print "Sorry! Username is taken! Create another."
        is_user_good = False
    if not 5 < len(user) < 25:
        print "Username must be at least 6 characters!"
        is_user_good = False
    if is_ascii(some_string="") is not True:
        print "Please create username that follows ASCII formatting."
        is_user_good = False
    return is_user_good

Determines whether the password is valid or invalid:

def is_good_password(password):
    count_upper, count_lower = 0, 0
    for characters in password:
        if characters.isupper():
            count_upper += 1
        if characters.islower():
            count_lower += 1
    is_password_good = True
    if len(password) <= 10:
        print "Password is too weak, must be more than 10 characters long!"
        is_password_good = False
    if set(database).intersection(password):
        print "Password Must Contain Alphanumeric Characters!"
        is_password_good = False
    if count_upper < 1 or count_lower < 1:
        print "Password must contain at least one uppercase and one lowercase character!"
        is_password_good = False
    return is_password_good

These two functions are amalgamated into one function to create a username and password:

def create_user(database):
    while True:
        user = raw_input("Enter a New Username: ")
        if is_good_user(user):
            print "Great Job! Username Successfully Created! Time to Create a Password!"
            break
        print "That's not a good username, please try again!"

    while True:
        passcode = raw_input("Enter a New Password: ")
        if is_good_password(passcode):
            print "Welcome! Username & Password successfully created!"
            break
        print "That's not a good password, please try again!"

    database[user] = passcode
    make_digest(password=passcode, salt=None)
    dump_data()

Should I add in a class for readability of my code? Being new at Python, I'd like to take up the challenge if adding a class is necessary.