There's nothing wrong with having lots of unfinished starts. The more experience you get with those first steps, the easier getting past it will be in the future. Failing faster is never something to be ashamed of.
But you do also need the insight of pushing farther to understand how to manage your time and how important each step actually is etc. The big picture stuff. That insight will make both these first and later steps easier.
I would pick up a much smaller project (not a book) and push through as much of it as possible in a short period of time (give yourself a harsh deadline). If that fails, try another with an even smaller scope. Go down to drabbles if you have to.
Find a level where you can push through, then use the knowledge and experience gained to work your way back up.
Besides that, try to understand that books are long-term projects. You're not going to complete them in one push of deep inspiration. That means you need to accept working on them when they're not very exciting, and being prepared for distractions.
Put some system in place to capture intruding ideas without obsessing over them. Maybe you dedicate 3 days to putting down everything you can about this new idea, then cut it off and return to the original project.
Leave the other as an aspirational project in the void, not an actionable thing in your schedule. You're not going to juggle 11 books at once as a beginner and do any of them justice.
Aside: Something I've personally done to make my ideas more manageable is to put all my stories in the same fictional world.
It does limit the scope of the stakes a bit (can't blow up Earth in '87 if I have a stort set there in the 2000s etc), but having persistent rules and recurring story elements means everything is connected and impactful.
Even if a particular story isn't finished and published, what was developed has a lasting background effect on the world and stories that come after it. This has helped me a lot as someone with more story ideas than I can realistically ever tell.
Not saying you should do the same, just that there are creative and fulfilling ways around the issue.