Yes. That's why River said she couldn't get involved until the end, when Melody had already been taken away. Otherwise she'd be crossing her own timestream Possibly. But so far adult River hasn't met her real baby self. She only met the flesh Melody.
Amy touched young Amelia in "The Big Bang" without ill effect, though as Rory might point out: in fairness, the universe did explode.
The Ninth Doctor also pointed out that the timeline was made particularly sensitive to damage as there were two versions of himself and Rose present at the scene. There is the possibility of damage to the timeline but this is presumably the reason River was not willing to go to Demons Run until the battle was over and Melody had been taken.
When Amy touched young Amelia, the universe had already exploded.
When Rose touched her younger self, she had already created the paradox that brought the reapers on the scene. We don't know that there would be similar problems if someone touched his/her younger self without there being a paradox involved. Note: I mean a paradox, something self-contradictory, not just something that would be impossible without time travel. Of course, care would need to be taken to avoid creating a paradox. Characters have previously interacted with their younger selves without creating a paradox.