Write an iOS, Android application, and the Web server back end for it

Good Afterrnoon, Hello, I am an 18 year old entrepreneur based in the US and I need your help developing an app. I am in the process of setting up my own little service for authors. I am hoping to find an app developer for BOTH ANDROID AND iOS for it since I've been searching for the right kind of app builder service, but none had fit my needs. I need an app developer that can and accomplish my idea. My main purpose is to connect authors and bibliophiles in one multi-functional app (social network).There will be unlimited users (since I have over tens and thousands of followers on Instagram that would like to sign up) in which they will have a profile page, news feeds, followers/following, etc. They will share photos (kind of like Instagram and WeHeartIt) and like/comment on the posts. There will be a side where users can upload content (like stories and articles) in a magazine like platform (Wattpad). Users can comment, add the story to their library, and vote. All of this will be organized by genre (for the stories by users and for authors) by the Newest/Hottest tabs. As for the articles, it will be organized by topic. This will contain posts of their reviews and authors will have advertisements of their works (On a specific page) and users can request to get an ARC copy (like NetGalley). In this process, users earn points for their activities and interactions and they redeem their points to get book items (It's like a store, but the users can either pay for the item or use their points). This is kinda like "a point rewards app for book lovers". The theme of this app will be colorful and bright neon and must have a responsive feel. Please keep in mind, that I am on a really tight budget since I am a college student.