I'm 27 this year too and also in your situation. But hey, nothing wrong with "being young" right? Everyone goes about life at their own pace. It's something you have to accept sooner rather than later.
If you feel behind, I'm assuming that you want something so go forth and get it!
Yup it's normal to feel that way. Remember that we are all born in different circumstance into different families, so our starting point is already different.
It's tempting and easy to compare ourselves with our peers but the best thing to do (which you probably know) is to just work on yourself and what you find most fulfilling within you. Sometimes, it's ok to just "be" too. You don't have to be something else. You can just be yourself and love yourself as you are.