Developed my first app using SQLite. Am I late into the game?

Yes you should have used a nosql database. Just kidding, better late then never, sqlite is awesome :)

Nope you are not late. Sqlite is good if use case is small

You shouldn't worry about what kind of store you use, if it takes off you can just switch to a more appropriate solution. Everything else is just optimizing to early.

sqlite is my fav for small offline projects.
Just consider that It shouldnt be used in network or multiuser apps and you must always close the database after use.

woo woooo good thing

Just because a technology is old it doesn't mean it's bad. All these modern languages, newer frameworks, hipper databases, ..., none are better! They're just newer. As long as you pick the right tool for the right job, it doesn't matter if you program your database in Basic or Excel. Just make sure you can fulfil the requirements!

SQLite is the best for mobile apps

SQLite is the perfect choice for that.

Firefox stores all of the data (bookmarks, history, etc.) in sqlite-format, google-chrome makes some use of it too and the kindle eReader are storing vocabulary with it.

I once did a simple notification android-app using sqlite. Even Android does provide decent built-in support for storing your apps data in sqlite-file rather than the default properties stuff.