In astrology Pluto is classified as a generational planet. Astrologers call a lot of objects planets. The sun and moon are colloquially called planets, but they used to be called “lights” and the planets “wandering stars”.
The sign that Pluto is in is shared by a large age group. It spends 12 to 30 years in each sign. You don’t say “I’m a Scorpio,” because you have Pluto in Scorpio.