Can I eat garlic mustard?

Yes, please eat it all.  Garlic mustard (Alliaria petiolata) is a horribly invasive weed. TPP must make the rounds of our estate two or three times a spring to keep the garlic mustard at bay; it invades from an un-kept preserve next door. It's a biennial taking two seasons to go from seed to seed. And, yes, especially when young the leaves are edible; they have a nice peppery garlicy flavor that would probably go quite well in wilted salad or in a pesto.  A young person asked about this.  They are fascinated with the idea of foraging for edibles. So, why not collect it and eat it?  Basically, it isn't that good that it's worth it.  Think about this. The plant is native to Europe where agriculture has been practiced for a few millenia.  The plant has long been collected as a culinary herb. The really good food plants have been domesticated and are grown at least in some places for food. But not garlic mustard. Our ancestors are telling us something, but by all means collect all the garlic mustard you want. TPP would recommend collecting along a section of a walking/biking trail built on an abandoned railway line. The banks of this trail abound (too weak), are a dense, weedy, morass of garlic mustard, and all these jogger/biker types zoom/zoom-zoom by thinking (?), isn't nature wonderful?  All the botanist sees is a mess of invasive weeds, and enough peppery, garlicy greens to choke the population of Chi-town.  
Understand TPP is not opposed to foraging.  Back in the poor graduate student days TPP foraged the country side for asparagus. Clumps grew along fences in the grassy margins of maize fields, so you could ride your bike along and harvest some spears returning home with a nice veggie for din-dins. The spears were hard to see in the tall grass, so TPP would bend a discarded can (all too common) over the fence to mark the spot when the asparagus shoots were tall and easily seen so you could find the young shoots next spring. This worked well until someone figured out the marking system and foraged earlier. So TPP does not intend to discourage foraging per se, but does have a thing about invasive plants and people's insensitivity to them. One friend says she can no longer walk in woods because she can't stop pulling garlic mustard or honeysuckle seedlings.