Am I 18/9 or 45/9?

So I’m born 5/31/2007, and I saw that if you add up each individual digit that’s how you get your life path, so I did 5+3+1+2+7 which equals 18.

But then I saw another day add up the numbers in this way: month + days + year which would be 5+31+9, which is 45.

So if anyone could help me out that would be appreciated.

And also if any one could share their experiences vein a 9 life path of maybe give me a reading that would be nice also