why my python code does not encrypt or decrypt my message


For some reason when I run the code at the end it just displays the message without encrypting or decrypting it im really confused please do not hate on me if this is really obvious I am very new to python and barely know the basics

#declare variables
NewWord =""
NewLetter = ""
SecretMessage = 0

mode = input("Please enter a mode: ").lower()  #makes it lowercase
message = input("Please enter a message: ").lower() # lowercase to tackle capitals
while True:
        offset = int(input("Please enter a number: ")) #If no exception occurs, the except clause is skipped and execution of the try statement is finished.
    except ValueError: #If exception occurs, the except clause continues printing not a valid number and letting you re-enter the offset and not just throwing up an error.
        print ("Not a valid number")
#print(mode, message, offset) #Test to check user Input

for letter in message :
    SecretMessage = ord(letter)
    if mode == "Encrypt" :
        SecretMessage += offset # add the offset to the letter
    if mode == "Decrypt" :
         SecretMessage -= offset # subtract the offset to the letter
    if SecretMessage < 97:
       SecretMessage  += 26
    if SecretMessage > 122:
        SecretMessage -= 26
    NewLetter = SecretMessage
    NewLetter = chr(NewLetter) 

   # print(newLetter)# check conversion
    NewWord += NewLetter


mode = input("Please enter a mode: ").lower()

makes the mode all lowercase which prevents it to equal either "Encrypt" or "Decrypt". So, your if clauses are not executed.