Nobody can tell you exactly when to buy. In comparison to the last few months the price is relatively low , you can buy some now and just keep adding to that stack every month. This way you can average the price you bought for.
This is a good strategy for someone new. Ultimately it could dip lower (please baby jesus, don't let it happen), but it does seam to be at a low point over the last little while.
I'd just go slow and steady, pay attention, and if you see things rising, try to invest more fast and furious.