Problem with creating dataframe in pandas

When I'm trying to run the following code:

import pandas as pd
import numpy as np

raw_data = {first_name : ['Ori', 'Tzachi', 'Gil', 'Stern'],
            last_name:['Raz', 'Nachman', 'Anconina', 'Tal'],
            age: ['30','30','31','31']}

df = pd.DataFrame( raw_data, columns=['first_name', 'last_name', 'age'])

print (df)


I'm getting the following output:

"C:\Program Files\Python36-32\python.exe" "C:\Program Files\JetBrains\PyCharm Community Edition 2017.3.3\helpers\pydev\pydev_run_in_console.py" 57669 57670 "C:/Users/Ori/PycharmProjects/First_Project_tryout/Python try 1.py"
Running C:/Users/Ori/PycharmProjects/First_Project_tryout/Python try 1.py
import sys; print('Python %s on %s' % (sys.version, sys.platform))
sys.path.extend(['C:\\Users\\Ori\\PycharmProjects\\First_Project_tryout', 'C:/Users/Ori/PycharmProjects/First_Project_tryout'])
Backend TkAgg is interactive backend. Turning interactive mode on.
PyDev console: starting.
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32
Traceback (most recent call last):
 File "C:\Program Files\JetBrains\PyCharm Community Edition 2017.3.3\helpers\pydev\pydev_run_in_console.py", line 53, in run_file
 pydev_imports.execfile(file, globals, locals) # execute the script
 File "C:\Program Files\JetBrains\PyCharm Community Edition 2017.3.3\helpers\pydev\_pydev_imps\_pydev_execfile.py", line 18, in execfile
 exec(compile(contents+"\n", file, 'exec'), glob, loc)
 File "C:/Users/Ori/PycharmProjects/First_Project_tryout/Python try 1.py", line 4, in <module>
 raw_data = {first_name : ['Ori', 'Tzachi', 'Gil', 'Stern'],
NameError: name 'first_name' is not defined




Anyone knows how do I fix this?