Personally, I think the system or website can do it. You can choose Android if you have a good foundation, because the requirements and difficulty of Android will be much higher.
If you don't attend classes, you will definitely have a poor foundation. It is suitable for choosing systems and websites, not Android or others.
For example, the languages are net, c#, Java, php, C, c++ and so on.
There are also frameworks such as mvc, ssm and ssh.
Design and Implementation of Teacher Query System Based on Java/c#/php
Design and Implementation of Teacher Evaluation System Based on Java/c#/php
Design and Implementation of Personnel Management System Based on Java/c#/php
Design and Implementation of Supermarket Management System Based on Java/c#/php
Design and Implementation of Mobile Phone Sales System Based on Java/c#/php
Design and Implementation of Device Management System Based on Java/c#/php
Design and Implementation of Online Shopping System Based on Java/c#/php
Design and Implementation of Electronic Reimbursement Management System Based on Java/c#/php
Design and Implementation of News Release Management System Based on Java/c#/php
Design and Implementation of Attendance Management System Based on Java/c#/php
Design and Implementation of Online Order Management System Based on Java/c#/php