Looking into getting a couple sheep

Just under a year ago, my husband and I bought a home with 6 acres and a half acre pond. Since then, we have added 20 chickens and 5 ducks to our family. We are talking about getting a couple sheep. Although, I have many questions.
I love to garden. We plant a wide variety of things and just last summer planted apple, pear, plum, and cherry trees. They are all just babies maybe a couple years old. Will the sheep eat them? My favorite apple tree was ripped to shreds last fall from a buck and I was heart broken. I really love my trees. I also planted grape Vines and a wide variety of perennial flowers. I am hoping to have a sustainable homestead within the next few years.
I do not know if sheep will be something that would bring us more good than bad.
Also, I have small children. A 5, 3, and almost 2 year old. My 3 year old has been completely traumatized by a rooster we had in the past and now has a fever of chickens 😫. I hope she will get over it this coming up summer but I do not want to risk having another aggressive animal in our yard. Can sheep be aggressive with children?
Thanks a bunch

My sheep killed many trees, even quite large ones.  Their favorite food was tree bark!

Don't get a ram lamb and raise him as a pet because he will likely be aggressive.  Sheep play by ramming each other, and they don't understand that humans are not as strong.  Getting rammed in the head can kill a human.  Both my husband and I were injured by our ram, who had been raised as a pet by his breeder's children.  Sadly we had to put him down because he was so dangerous.  

If you want tame pet sheep you will need to buy young lambs or sheep who have been raised as pets from the beginning.  Our sheep (other than the ram) never became very tame.

Sheep or no sheep, as you noticed, deer are rough on young trees.  Where I live there's also elk to contend with.  They got so bad with tree damage that G&F actually paid for my neighbor to get a perimeter fence for his 4.5 acre lot.  4' field fencing with 3 high tension hot wires above that for a total of 7' height.

Anyway, if you want those young trees to live long enough to be immune to livestock like sheep and wildlife like deer you'll have to fence them to prevent access.  There is a breed of sheep (Shropshire) reputed to leave trees alone.  However I have no experience with those sheep (or any sheep, yet, but planning to get some myself soon) so take that for what it's worth.

Any animal can be aggressive to humans.  The more they are socialized to people, generally, the less likely you are to have problems.  However then you can get into dominance issues as mentioned by Tyler.  It is possible to stop those problems, but you have to know the right way to react to a dominance challenge and that will be different for each species, and sometime for different breeds within a species.

Do you have a certain use that you want the sheep for? Meat, fiber, milk, all of the above? Many breeds have different traits and characteristics but my experience is they are great for a garden as long as they are kept out of it and the only part of them going into it is their cured manure. We have ponderosa pine in our pasture and the saplings do not stand a chance unless fenced, screened, tubed, something to keep the sheep off. If you have perimiter fencing already for them then some temporary electric mesh screen might be a good option as you can form temporary pastures and rotate them more often.

Sheep are great, we found a local shepherd near our area who had the type we were interested in and she was very willing to share knowledge and educate us.

Nice looking sheep there Perric!

Myself I really like having sheep, but I grew up on a dairy farm and found sheep to be a lot less intimidating compared to cows.

Thank you all for the replies. After discussing with my husband, I think we are going to wait a while before getting sheep. I love the idea of adding to our little farm, but I think starting with the lowest maintenance animals is the best idea while our kids are so young. I think a good dog is what we need next.