I figured out the book cover deal. However, I'd like it bigger.
To be blunt, the problem is not so much about the size of the image, as it is with the design.
The typography is lost in the blur of the image.
The image lacks contrast. It also doesn't clearly clearly identify the genre; covers are specifically associated with genres.
Readers depend on cover themes/tropes/styles fo identify genre—there's nothing about this one that "speaks" to the reader in terms of genre.
There's a reason that cover artists are a very specialized niche.
It's a very specific collection of skills.
Go to your local bookstore. Look at the covers. Look at the covers for the titles that are selling in your genre.
These cover images are all smaller than yours:
This last one is a bit larger than the others: but while it's archaic in terms of sensibility, look how easily recognizable it is. It's not a paranormal YA—but it's pretty clear what genre it is.
I beg of you,
please, hold off on self-publishing.
Really.
You haven't really even
begun in terms of revising, and beta readers, and finding an agent.
I'd hate to see you blow a genuine opportunity. You can always choose to self-publish.
But you can't always choose to commercially publish.
For YA novels, in particular, this is a bad decision. YA novels are mostly purchased by libraries, and in hard cover.
Hardcover means larger advance, and larger royalties.
And you'll still have the chance to epublish—but to epublish with a trade/commercial publisher, and their marketing and sales departements, supporting you.
While you work on the sequel, which will require care, and diligence, and expertise.
Why waste your opportunity?