Just want your opinions about my code. How could I improve it? Is there a better method to do it? I'm learning python and I appreciate your opinions, thanks.

    from sys import exit
    from random import randint
    
    print "Welcome to the PIN Game 1!"
    print "Tell me your name"
    
    user = raw_input('> ')
    
    #asks the user for an entry and prints what he has chosen
    def start(): 
    	print "%s, choose one of the options: " % user
    
    	print """
    	1. Rock
    	2. Paper
    	3. Scissors
    	"""
    
    	choice = 0
    	cpu_choice = randint(1,3)
    
    	while choice <= 0 or choice >= 4:
    
    		choice = int(raw_input('> '))
    		if choice == 1:
    			print "You chose ROCK!"
    		elif choice == 2:
    			print "You chose PAPER"
    		elif choice == 3:
    			print "You chose SCISSORS"
    		else:
    			print "What is your problem? Try again, this time choose a number between 1 and 3!"
    	cpu_decision(cpu_choice)
    	result(choice, cpu_choice)
    
    #random cpu input
    def cpu_decision(cpu):
    	if cpu == 1:
    		print "Your opponent chose ROCK!"
    	elif cpu == 2:
    		print "Your opponent chose PAPER!"
    	else:
    		print "Your opponent chose SCISSORS"
    
    #if user loses
    def lose():
    	print "Sorry, you lost the match"
    	
    #if user wins
    def win():
    	print "Congratulations! You beat your opponent!!"
    	
    #prints the result
    def result(user, comp):
    	if user == comp:
    		print "Gee! You tied!"
    	elif user == 1 and comp == 2:
    		lose()
    	elif user == 1 and comp == 3:
    		win()
    	elif user == 2 and comp == 1:
    		win()
    	elif user == 2 and comp == 3:
    		lose()
    	elif user == 3 and comp == 1:
    		lose()
    	elif user == 3 and comp == 2:
    		win()
    	
    	again()
    
    #ask if the user wants to play again
    def again():
    	print """
    	Wanna play again?
    	1 for YES
    	Anything else to quit
    	"""
    	
    	again1 = int(raw_input('> '))
    	
    	if again1 == 1:
    		start()
    	else:
    		exit()
    	
    start()