Hello beeulah,  

Mobile app developer and fashion technology both have good scope. If you become a mobile app developer, you will be considered as successful based on the reach of the app and the no of  people who use it. When you decide to be one you should keep on creating more apps. Similar to fashion technology you have to keep on making new styles. So being innovative and creative is essential for both of them. Both have a good scope. I will suggest you to move on with your interest,  chose the one which you like more,  which you feel you don't need to pressurise yourself for the job rather you must enjoy doing the job. So think and decide.  All the best!!