Not if you go faster than the speed of light. Or if you happen to have a flux capacitor and 1.21 jiggawatts, you could do it at 88 mph

*FWEEEEEEEEEEEEEEEEEEEEEEE pop* I've arrived! See? Forward time travel is possible.

I will now travel 1 minute into the future. See you there! *FWOOOOOOOOOM*

It's been proven since the beginning of the universe.

Terminator 2, mother-blam!-er.

[i]You're[/i] a concept with no real definition. Time has a pretty solid one. It's... you know... time... It's a dimension through which... events... progress... linear-ly... ... Okay, so it's a fairly abstract definition, but it's still pretty solid. I certainly don't think it's wrong to say that we're all travelling forward through time.