Python 3.6 def errors

I am creating a python script for science fair that surveys someone on their health and determines their risk of type II diabetes. I am assigning a point score to each question, but it's not letting me add to the score.

Here is my code:

score = 0

def DiabAns():
    score = score
    if score == '0':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 0-10% chance of developing diabetes. ")
    if score == '1':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 0-10% chance of developing diabetes. ")
    if score == '2':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 0-10% chance of developing diabetes. ")
    if score == '3':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 11-20% chance of developing diabetes. ")
    if score == '4':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 11-20% chance of developing diabetes. ")
    if score == '5':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 11-20% chance of developing diabetes. ")
    if score == '6':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 21-30% chance of developing diabetes. ")
    if score == '7':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 21-30% chance of developing diabetes. ")
    if score == '8':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 21-30% chance of developing diabetes. ")
    if score == '9':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 31-40% chance of developing diabetes. ")
    if score == '10':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 31-40% chance of developing diabetes. ")
    if score == '11':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 41-50% chance of developing diabetes. ")
    if score == '12':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 41-50% chance of developing diabetes. ")
    if score == '13':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 51-60% chance of developing diabetes. ")
    if score == '14':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 51-60% chance of developing diabetes. ")
    if score == '15':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 61-70% chance of developing diabetes. ")
    if score == '17':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 61-70% chance of developing diabetes. ")
    if score == '18':
        print("Judging by your score of "+str(score)+", it has been determined that you have a 61-70% chance of developing diabetes. ")

def Test():
    ans1 = input("Question 1: What is your BMI (height/weight)? Your Answer (numbers only):  ")

    if ans1 >= '35':
        score = score+5     #####SCORES ARE COMPLETELY BASED OFF OF ESTIMATE OF PERCENTAGE OF RISK FACTORS AT THE MOMENT. WILL IMPROVE LATER.#####
    if ans1 <= '35':
        score = score+0

    ans2 = input("Question 2: Has anyone had Type II diabetes in your semi-immadiate family (mother, father, sister, brother, cousin, aunt, uncle, grandmother, grandfather)? \nYour answer (y/n): ")

    if ans2 == 'y':
        score = score+3
    if ans2 == 'n':
        score = score+0

    ans3 = input("Question 3: How old are you? Your Answer: ")

    if ans3 <= '40':
        score = score+0
    if ans3 >= '40':
        score = score+3
    if ans3 <= '10':
        score = score+1
    if ans3 <= '10':
        score = score+0

    ans4 = input("Question 4:Is your race African American, Asian American, American Indian, or Hispanic? \nYour Answer (y/n): ")

    if ans4 == 'y':
        score = score+2
    if ans4 == 'n':
        score = score+0

    ans5 = input("Question 5:How much would you estimate that you excersice a day? \nA) 0-10 minutes \nB) 11-20 minutes \nC) 20-40 minutes \nD) 40-60 minutes \nE) 60+ minutes \nYour answer: ")

    if ans5 == 'a':
        score = score+5
    if ans5 == 'b':
        score = score+4
    if ans5 == 'c':
        score = score+2
    if ans5 == 'd':
        score = score+0
    if ans5 == 'e':
        score = score+0

    ans6 = input("Question 6: \nHave you previously in your life had prediabetes? \nYour Answer (y/n): ")

    if ans6 == 'y':
        score = score+6
    if ans6 == 'n':
        score = score+0

    ans7 = input("Last Question! \nQuestion 7: \nHave you had gestational diabetes if you were pregnant? \nYour Answer (y/n): ")

    print("Calculating general percentage... ")

    if ans7 == 'y':
        score = score+3

    if ans7 == 'n':
        score = score+0
    DiabAns()

def PreST():
    preans = input("Welcome to the Type II Diabetes Predictor! Hit Enter to continue. ")
    preans1 = input("First,there are some rules we will have to go over. Hit Enter to continue.  ")
    preans2 = input("Rule 1: Always type in lower case letters. Hit 'Enter' to continue.  ")
    preans3 = input('Rule 2: When it says "Hit Enter to Continue," you do it. Hit Enter to continue. ')
    preans4 = input("Are you ready for the Test? (y/n):  ")

    if preans4 == 'n':
        print("Too bad. You got yourself into this, now you will get yourself through this test.")
        Test()
    if preans4 == 'y':
        print("OK. Let's begin! Hit Enter to Continue. ")
        Test()

PreST()