Yes Windows 10 is out and yes there is a very good chance your computer is compatible and ready for the upgrade. As I posted some time ago, you will notice the windows 10 icon in your system tray. This is how you will know when it is ready to install.
Microsoft will NEVER email you directly and even if they did, they would never provide links that you would click on to start installing.. As reported by Gizmodo here, it appears the scammers are doing their best to take hold of your computer for what is known as ransomware.. don't fall for it!
Just relax and don't be in a hurry to get Windows 10. Since it will arrive through the normal windows update channel, you will get it sooner or later.