In the second picture, that bunny only looks to be about 3-4 weeks old, but in the first picture it looks to be older then that, so it's kind of hard to tell unless you want to post a few more pics. If it really is that young, you may encounter some eating and health problems with it, as that is far too young for a bunny to be weaned and away from its mother.
If it is only 3 weeks old, you will probably have a pretty hard time determining it's sex. Even experienced breeders can get it wrong until the rabbit matures more and it becomes easier to tell if it's male/female.
I agree that veggies aren't a good thing for it until it's older, though there may be an exception. Usually pellets and hay are what you want to feed it. It would be best to start it with a grass hay like timothy, but if this bunny is really that young, it may have difficulty eating hay, or even may not be used to it and not know how to eat it. If it will eat grass hay, that's what I would start it on. If it won't, you may have to try something else. You may even need to feed veggies if that is the only solid food it is used to, but that would be the only reason I would feed such a young rabbit veggies. If you do end up having to feed veggies, don't feed carrots( or anything else sugary as it can disrupt the gut flora and cause runny poop or digestive problems) or iceberg lettuce(which can cause diarrhea and can be fatal to rabbits). It would be better to stick with dark leafy greens like parsley, cilantro, dark leafy lettuce, and try to introduce only one veggie at a time. And keep a really close eye on it's poop. You don't want to be seeing any mushy poop.
If your bunny will eat the grass hay, then start with that. Then you can gradually start introducing alfalfa pellets into the bunny's diet. You want to start out with a very small amount, like a pinch, and gradually increase that amount each day to give the bunnies digestive tract time to get used to the new food. Suddenly introducing pellets into a rabbits diet can often cause digestive upset and other issues, so best to go slow. You want to work up to feeding an amount that will last most of the day. It's better though to not give unlimited amounts of pellets as you still want the bunny eating some grass hay so that it is getting enough fiber. With my baby bunnies, I fed twice a day, and enough pellets so that they would run out about 3 hours before the next feeding. Then in that time they could snack on their grass hay to get their fiber. I know some places recommend also feeding baby bunnies alfalfa hay along with their alfalfa pellets, but in my experience having so much alfalfa in their diet is too rich of a diet and can sometimes cause some digestive issues. They are already getting plenty of calcium and protein from their alfalfa pellets, so I don't feel alfalfa hay is also necessary. I've found that grass hay with the alfalfa pellets works best. Though if you do decide to feed alfalfa hay, it should be introduced gradually in small amounts, like the pellets, as it can sometimes cause digestive upset if introduced too quickly. Grass hay on the other hand, is almost always well tolerated by rabbits and doesn't need to be gradually introduced into the diet.
You will also need to make sure it is drinking ok. If it is only 3 weeks old, it may not have learned that yet from it's mother.
