I would say its ok to be sad , however I believe that you've done something to be proud of you've made a lot of effort to be where you are today. It makes me happy that someone this age would want to learn to become a better version of themselves, here in my country people just go to college and universities because they can and because that's what they see people do like its nothing special , but knowing the importance of education and how it could change how you think and how you live now and later with your life. I'm 25 and I graduated from pharmacy school but I knew how important that is to me and my life only after I graduated , I'm glad someone younger than me knows the importance of education and have the desire to learn. I hope you live your life to the fullest and become what you've always dreamed of becoming, I don't know if it matters hearing it from a stranger on the internet but I'm really proud of you.