Designing a 50Ω coplanar waveguide on 1.6mm FR4
Your trace width and spacing calculate out as a 50 ohm trace on a couple of calculators I checked, so that should be okay.

But I see a couple of other issues you should look out for:


In the original design, the return path is broken due to the cut-out around pad 4 of the antenna.
As shown on the app note from the vendor, the matching network should be as close as possible to the feed point of the antenna. The antenna is designed with plenty of space to fit the components beneath it. How to convince your CAD tool to allow this without a DRC error I don't know.
As shown in the app note from the vendor, the ground beneath the antenna component should be solid. This means the trace should be moved to an inner layer or the back side of the board. 
With the matching network placed under the antenna (according to vendor recommendations), you may have to remove the antenna to adjust the matching network during tuning. Given the heavy thermal mass of the antenna and the un-connected pads that it mounts to, the pads are likely to lift when you try to do that. Be prepared to discard several boards if you have to tune that matching network.