like ishmael said, stars don't measure your worth. there's a very good chance that the only reason pluto has more stars is because she's been here longer. also, some people don't star very many posts (no matter how much they like the post). nacho, lots of people may still like your posts and just choose not to star them for some reason. and a lot of people star every post they see, no matter how they feel about it. pluto may just have gotten lots of stars from these people.
there are also other reasons you could have less stars than other people. for example, i have been here for two years now and i don't have nearly as many stars as most people. one big reason for this is because the people who usually star your posts are your forum friends. one of my best friends on here, sanetra, has a glitch on her computer that makes it so that she can't star any posts. so one reason i don't have very many stars compared to most people who have been on the forums for the same amount of time as me, is because one of the people who would probably star more of my posts than anyone else, just can't use the star button.
all that goes to show that stars aren't a measure of how much people like you or your posts. pluto may always have more stars than you, nacho, and that's okay. and there may be a day when you have more stars than pluto does. either way, we still love you the same.
hopefully that made sense and could help a little bit. have a nice day!