For some weird reason, there's a pernicious rumor going around that you may not, under any circumstances, charge on the first turn of the game. I've heard this repeated several times recently, so I think it's time to post something up because this is completely untrue.
- You may not charge if you have just arrived on the table whether from deepstrike or whatever.
- You may not charge if you disembarked from a non-assault vehicle on your turn or on your opponent's turn (due to shooting).
- You may not charge on the first player turn if you used Scout.
- You may not charge on the first player turn if you used Infiltrate.
Of course, there are individual unit rules which break some of these rules, but that's neither here nor there. There are also few other rules which keep one from assaulting, but these are the only ones that have really got to do with appearing on the table.
At any rate, there is not a single rule that forces a blanket ban on first turn assaults. If your opponent comes too close, it's on them for doing so.
Remember, your opponent must always show you where the rule is; you don't have to show them where the rule isn't.