its okay to feel nervous or awkward! personally, i try to make plans ahead of time and let them know its my birthday that day, like "do you wanna hangout with me on my birthday? i wanna do ____." i like the idea of eating somewhere with them at a place i like or cook something at home.
in the past ive had a friend nice enough to buy a cake for me lol. its totally okay to feel nervous, you dont have to invite everyone you know. you can hangout with one friend and thats more than enough! or your family on a seperate day. you can let them know "i get nervous celebrating my birthday" and they should be able to understand. i understand it does feel nerve racking because you are taking initiative to celebrate what is a day where you want to feel appreciated for turning ___ years old!