Putting a variable into a string (quote)

You should use a string formatter here, or concatenation. For concatenation you'll have to convert an int to a string. You can't concatenate ints and strings together.

This will raise the following error should you try:

TypeError: unsupported operand type(s) for +: 'int' and 'str'

Formatting:

quote = "You are %d years old" % age
quote = "You are {} years old".format(age)

Concatenation (one way)

quote = "You are " + str(age) + " years old" 

Edit: As noted by J.F. Sebastian in the comment(s) we can also do the following

In Python 3.6:

f"You are {age} years old"

Earlier versions of Python:

"You are {age} years old".format(**vars())

This is one way to do it:

>>> age = 17
>>> quote = "You are %d years old!" % age
>>> quote
'You are 17 years old!'
>>>