Of course it is a reboot. Not sure why this is even an issue. We all knew it was a reboot. Not a remake, but a reboot (a film that is simply restarting the franchise, not redoing the events of the first film).
Source: Comic Book Movie
While we wait for the next official announcement, actor Sam Neill - best known for playing Doctor Alan Grant in 1993's Jurassic Park and 2001's Jurassic Park III - told Stuff.co.nz that he will unlikely reprise the role for Jurassic Park 4. He doesn't detail why, but hints at the reason in a brief comment. "I'm told it's a big reboot, a total re-jig."When enough time passes, any sequel can be considered a reboot. Hell, look at Texas Chainsaw 3D, Scream 4 and even Superman Returns. Yes, they're all sequels...and reboots. Calm down, Sam Neill.
Source: Comic Book Movie