The questions kinda hard to answer due to unknown variables like proper lighting, ideal enviroment, and plant health during flowering. Your plants look healthy, which is a really good start, but you wouldn't be able to even properly guess right now, because of how early it is.
You'll get one marijuana! Seriously though, it depends on how long you keep vegging em up to a point. Depending on your light, if you were to start flower today, then you would pull about a pound. Nah, honestly, if I had to guess, it will probably be somewhere between 3-6 ounces dry weight if you got like 400 watts of light. Maybe 8-15 ounces if you have 1000 watts, if you're lucky and they finish trong. Lol, don't worry about how much you'll pull. Just don't kill them and after some growing experience you'll be able to eyeball plants and estimate a wet weight at harvest. Then how you cure will effect the final weight. I'm a fairly inexperienced grower, about 6 months of growing experience. Anyway, not worrying about harvesting pounds was a hard lesson, but it makes growing less stressful.