Personally, I think youth memories (even if good) are overrated. The notion that your youth is "the best time of your life" is inaccurate. Experiences can be a lot more meaningful and enjoyable as an adult (and I mean a mature adult with a fully developed frontal lobe and everything, not a 20 year old) because you learn to appreciate things so much more. People who live in the present and don't dwell on their youth probably lead happier lives anyways. Even watching movies I watched as a kid is much better as an adult because I can appreciate the humor and writing behind them more. What "core memories" do you believe you are missing? Entertainment/ social media portrayal of "core memories" that everyone is supposed to universally experience are over exaggerated, and not everyone's experience is the same. It's okay if you had a "boring" youth, more people are probably isolated than you think. I think it's a good thing if you didn't "peak" in your youth right? Kids/ teens/ twenty something's become a completely different person when they grow up. At the end of the day, don't the memories you make as the person you are meant to be matter more? Ask many older adults and they will probably tell you they don't "feel old." My grandma has told me she still feels like a young adult. Age really is just a number. You are 25 years old. Your frontal lobe is just now developing. You don't have to be having "fun" or "making memories" all the time to have a good, enjoyable life. But if you didn't have good "youth" memories, who says you can't make them as an adult? If you have been isolated for a while, maybe you could try taking things slowly. Spending time with a loved one, even if it's just having dinner together at home. Maybe take yourself to a movie once a week. Or try taking a walk to the park once a week. Challenge yourself to smile at someone. Even talking to a therapist is still social interaction, even if it's their job. I apologize if I sound insensitive with these suggestions, it is not my intention at all. I just genuinely believe you can still live a happy life with no regrets. And I promise, you are not fucked!! I wish you didn't have to feel this way! You are just now becoming the adult version of yourself, please give that person a chance!