Welcome to the forum and I am so proud of you that you have been able to purge this here and been able to get this out and off your chest. It is not easy to admit that you are making up stories and telling lies and I am super proud of you, with this move of admission and that you want to end this lying you can start a conscious effort each day to stop. I want you to know though that this is pretty common, especially when we may not be living a life that we want so badly and we tend to make things up that elude others to a life that we would love, that we don't have. This does not make you a bad child at all, it makes you a person who is craving to have something else in her life.
I am wondering how you would feel about having this conversation with your parents, it seems to me that they have chosen you, they adopted you and that is pretty special. I am sure that they do not think you are a bad child either, but maybe they do wonder what is troubling you and what you are thinking and what you are feeling.
It is hard to have these conversations and you could even start by showing them exactly what you have written here, that you do just want them to be proud of you, while I am sure that they already are, maybe they need to know that you are not feeling like they are proud of you, that letting them know these feelings can infact help them to in communicating with you too.
I hear what you say in that all the lies and telling people who love you these lies is really hurting how you see yourself and how you feel about yourself and that is really hard to hear. These lies are not who you are, they are not what you are and they can be corrected. You are so very aware now of the lies that you are telling and this is a really wonderful start. You can start even if it is one a day, when you feel you are about to say something that is not true you can stop, take a breathe and chose not to. Even if you say nothing, you can ask for a minute to respond, you can even say can I have some time to get back to you on that, if telling the truth hurts too much.
You are a young lady with alot on her plate and I am so pleased you have come to share how you are feeling so openly and so honestly, you matter and you are worth happiness Olivia.
I hope you can take some kindness for you, you deserve it.
Chat some more to you really soon Olivia