I couldn't be more proud of you! You did it! You got the job!
Getting a job is concrete proof that you have done some things right in the past and you have potential to learn and do more things right in the future. Someone gave you the job because he or she thinks you have the skills to do the job and meet the needs of the company, group, or team. He or she thinks that you have good character, that you will show up on time, work hard, and finish what you start. He or she thinks that you are likeable and good company.
Think about what got you to this point. You didn't get some jobs but you kept applying and interviewing. You faced rejection but you kept confident and didn't take rejection too personally. You were humble, asked for feedback, and learned what you had to do better, how to improve, and what to expect. You did lesser jobs well and suffered through rotten jobs, trusting that somehow they would help you to prove yourself in the future.
There is little in life that is as sweet as landing a well-earned job! Enjoy this moment and make the most of this opportunity!