HI Javan!
Welcome to Xojo! In general, if you are new to development or just to Xojo, start here. Access the free textbook Intro to Programming with Xojo. Join us for free webinars or watch on-demand videos covering a range of topics from intermediate to advanced.
When you are ready to build your app, find details about our licensing and pricing at the Xojo Store. All Xojo licenses are covered by our 90-day money-back guarantee. And you are welcome to email me at hello@xojo.com anytime you have any questions 
As to why you should use Xojo:
The Tool
As you evaluate Xojo, consider what you get in this one development language - the ability to compile for macOS, Windows and Linux plus the ability to develop for web, Raspberry Pi and iOS (Android coming soon).
Build apps with native controls so your app looks and feels right on any platform. From resources for new coders to advanced features like inheritance, interfaces and polymorphism for more experienced developers, learn and develop faster with Xojo.
The History
Consider the competitors Xojo started out against in the 90’s - which of those tools are currently supported, which are still owned by the same company and which are growing? Not VB6, not Apple’s MPW, Borland Delphi or Metrowerks CodeWarrior - it’s Xojo.
Betting on a well known tool, from a big company doesn’t necessarily offer long-term security or support. We’ve been around for 20+ years, we added iOS and Raspberry Pi support within the last few years and we are planning for the future of Xojo with Android support coming up next.
*edited to add more info!