We'd rather explain this than have you find out and stop trusting the result.
Your score estimates the shared, structural layer of facial attractiveness — how a panel of raters would likely score this particular photo, based on measurable traits. That's a real signal: research consistently finds substantial agreement about facial attractiveness both within and across cultures.
What no test can measure is the individual layer. A twin study published in Current Biology found that most reliable variation in personal face preference traces to each person's unique environment and life experience — the faces they've encountered, their particular social history. That information isn't in your face, so it can't be in your score.
So: treat your result as one data point about structural convention. It is not a verdict on your appeal, your prospects, or your worth. Anyone claiming to predict whether a specific person will find you attractive is selling something that doesn't exist.