It is not a juvenile Sharp-shinned Hawk. The Sharp-shinned Hawk is a member of the Genus Accipiter. The family that includes the Sharp-shinned Hawk, Cooper's Hawk, and Northern Goshawk. These three species are unique in that they all share yellow eyes as immatures. This bird in the above photographs is an immature, but has brown eyes. Which means that is in the Genus Buteo (the Latin name for buzzard). This genus includes the larger hawks like Red-shouldered Hawk, Red-tailed Hawk, Swainson's Hawk, Rough-legged, and Ferruginous Hawk (North American species). But also includes many, many more Old World buzzards and African species.
An immature Broad-winged is very similar to an immature Red-shouldered. But the difference is that a Broad-winged has much thicker banding on the tail, and the banding tends to stay horizontal to the tail. Comparing that to this image, this bird has thinner banding and at more of a diagonal banding pattern to the tail. On top of that, a Broad-winged has a whiter chest with tear dropped shaped markings instead of the triangle/diamond shaped ones of a Red-shouldered. They will also have a stockier appearance than a Red-shouldered.
Time of year is also a good factor to go off of. Red-shouldered Hawks live year round in the states, but Broad-winged Hawks only live there during breeding season (summer) before migrating to Central America for winter. Most Broad-winged Hawks should have moved out of the states by now. Of course, Florida is a major migration route for the Broad-winged Hawk and a few birds could easily winter over. However, this bird is a Red-shouldered Hawk.
hope this helps 