Should I use my personal Apple ID for development or create a new one?
There isn't a hard and fast rule, or many convincing arguments in either direction. However, if you eventually want to make money or work with others, or in general grow in that direction, you may find that the ability to keep your personal and work stuff separate to be helpful. 

A simple example may be that you have personal pictures on iCloud associated with your personal ID, and for whatever reason, you want to give someone complete access to your development account without access to iCloud. Yes, there are other ways to accomplish that, but having the option of two different Apple IDs might come in helpful down the road.