I've been working for around a year now, and I feel like there's a big gap between where I am now and where I should be in terms of skill level. I'm getting good feedback at work, but there's just such a huge gap between the senior engineers on my team and me - It all feels really daunting. How do I know if I'm good enough, and what can I do to feel better here?
Ask. I feel like I’ve started a lot of answers this way, but we here cannot know if you are before above, below, or at the expectations your manager and team have.
Ask your manager what your growth areas are, and if they are far below expectations, or at expectations but would make you really stand out. Ask what you are best at, and if you can leverage it differently to help your team.
Ask the same to senior engineers on the team.
It seems like you’re probably doing well, but expect to be where people with a lot more experience are. Be the best you, not better than people that had a huge head start on you.
When it comes to improving and working toward your first promotion, I am sure there are a ton of more detailed posts here for that. That is growth to the next level though, not to overcome performance problems, which I don’t think is where you are.