03 Neon Fuel Gauge problem.

I just got a 03 Neon SXT. It's a great car and loving it. It has one small problem that I was hoping you guys could help me out with. The fuel gauge is off. I can fill the tank and the gauge goes almost to the full. I can drive it until the fuel light comes on and tank will only take about 5 gal to fill it back up. I think this is the fuel sending unit, but I'm just amateur at working on cars so I wanted to get a 2nd opinion.

How many miles are you getting from when you fill up till the light comes on again?

around 200 miles