I understand what you're saying.
My daughter is 22. She's been away at university for the past 5 years. Each of those years, she's wanted a dog. Freshman year, she bought & snuck a hamster into her dorm for company, but it just wasn't the same as a dog.
She just graduated last month & has started a new job with great pay & some flexibility in her daily schedule, meaning she can go home for a long lunch if she wants. So, she's buying herself a puppy. She is so beyond excited! But, she questions if she's ready to raise a pup by herself, be completely responsible for it, & train it herself. She's just questioning because she's never done it yet, but I know she has the skills to do it. If she didn't question herself, like you are, then I'd be concerned, because she wouldn't appreciate the gravity of what she's about to take on.
The fact that you're thinking about the impact having a pup will have on your life, shows that you're understanding what's involved in taking care of a pup and are aware of the commitment it takes to be a responsible pet owner.
Congratulations! I'm sure you'll be an awesome mommy
