Yes, it can be hard being an adult. And, no, I cannot do it for you. But I can offer some ‘sage’ guidance.
First, accept you are a grown up despite your tender years and reticence. There are literally millions of people exactly your age. In some cultures, and in prior times, you’d be considered nearly ancient.
Until you are an old, old person, struggling to determine which is the phone and which is your sweater, you are and will be responsible for yourself. I pray I’ve taught you not to expect or rely on a mate or any others to take care of your business. You will learn to do it better, with fewer missteps, less angst and more grace with each experience.
Second, all the ‘adulty’ stuff you need to do is simply the stuff most everyone your age, stage and lifestyle is doing: renewing your license and car registration; getting insurance for car, health, your stuff; renting an apartment or getting a room in a house; navigating work expectations and your own vocational goals; learning how to get along with fellow adults, each with their own goals and struggles.
The world is a very different place from when I was your age. Most of my past advice is precluded by technology and systems that are far less personalized than what I encountered. Which leads me to Guidance III:
Behind those screens, phone menus and keyboards, are people. Programming those systems are people. People still run the show. When the electronic version isn’t giving or taking what you need, connect with a person.
Push 0 when calling if the menu isn’t addressing the subject of your call; ask for a supervisor, get out of your car, off your laptop and go into the store, bank, bureau, hair salon, whatever. People generally want to help others; it makes them feel proud of themselves. Give them the opportunity to help you. Write down the name of the person with whom you are dealing; talk to them by name and thank them.
Fourth, except in the workplace, you are the Consumer. The people you are connecting with during your ‘adult’ business, rely on your needing their service, product, or governance. It’s their job to satisfy your given need or question. If not for your business needs, they don’t get a paycheck.
Always use your excellent manners, showing respect for others’ position, authority, and personhood in their workplace, but remember, you are the one with the power. That’s the upside of adulthood. You are powerful, your own ultimate authority. At last, you are the boss of you.