To update a gallery:
Go to:
https://upload.e-hentai.org/manageFine the gallery and click on "Manage"
on that page, see:

After adding any required files and saving & publishing, the gallery will update. It will replace the old gallery, and historic versions will be linked to the gallery.
If a gallery is locked, usually from latest version being aged for ~1 year, you may need to create a separate gallery, in which case the older would get manually expunged by the community. There is no penalty to you for this.
During this stage it should let you change the name, but if it doesn't, or the only thing you want to change is the title without changing the content, you can submit a rename request by clicking "Petition to Rename" when browsing the gallery.
Re "shy girl", a list of current fetish tags can be found here:
https://ehwiki.org/wiki/Fetish_ListingNew fetishes are not added freely as they first require discussion and support from the community before they can be activated.