Archaeology staff at the Burke estimate the point is at least 4,000 years old, and may be up to 7,000 years old. The discovery of the point is consistent with other archaeological data from around campus that show that Native American people lived on what are now the grounds of the University of Washington. An "Indian Trail," documented by maps from the Historic General Land Office (below), at one point bisected the UW campus area, and ran not far from where the projectile point was found.
(click to enlarge image)While other archaeological materials have been discovered on and around the UW campus, this is the first find in many years. Modern archaeological practices require diligence when recording and documenting archaeological sites, so the information gathered about this site is much more specific and useful to understanding the history of the landscape on which the UW is built than other finds have been. Burke director Julie Stein, an archaeologist herself, pointed out that other artifacts from around campus have a very vague provenance, such as "near the fountain." The University has now promised to survey that area and other parts of campus with pending construction projects for other potential sites.
The student who found the point, and the greenhouse staff who advised her, were definitely right to contact the professional archaeologists at the Burke Museum. It is illegal to knowingly disturb an archaeological site, and if you think you have found something, the archaeology department here can advise you how to handle the situation.