IRCC considers points at the time of ITA. So if you receive ITA after your birthday, you will lose the 5 points. But don't worry, even a score of 447 is excellent and is almost certain to result in an ITA in the next draw. Many of us, especially myself, would love to have even 437 points. I am almost 10 years older than you and will lose 11 points on my next birthday, and I am currently at only 410. I suggest that you start getting your post ITA documents ready (especially the PCC and medical exam) now because you will be getting an ITA soon, even if it's after your birthday.