At least around Austin, you can usually find some in bloom in pots in large commercial nurseries like Home Depot, and we have even seen them for sale on the front porch of grocery stores. We can guarantee neither availability nor endurance of the plants in pots in either case.
We love school projects on wildflowers, but you are suffering from a couple drawbacks. The first is, as you can see from this USDA Plant Profile Map, Lupinus texensis (Texas bluebonnet) do not grow natively anywhere close to Potter County.
We suggest you read the descriptions of the climate and soils in the Texas Rolling Plains as well as this one of the High Plains. Amarillo is right about on the border of the two. Then go to this plant link Lupinus texensis (Texas bluebonnet) and read the growing conditions for bluebonnets:
"Water Use: Low
Light Requirement: Sun
Soil Moisture: Dry
CaCO3 Tolerance: High
Soil Description: Limestone/chalky, Sandy Loam, Limestone-based, Calcareous, Sandy, Medium Loam, Clay Loam, Clay, Caliche
Conditions Comments: Not only does the state flower of Texas bloom oceans of blue, but this famous wildflower forms attractive rosettes in winter. This is the species often used by highway departments and garden clubs. If planting this species in areas where it has not formerly grown, it may be helpful to inoculate the soil with a rhizobium (soil-borne bacteria which form nitrogen-rich root nodules) for lupines."
This flower is an annual, which means it blooms fast, makes seeds that can last several seasons in the soil and dies. A potted blooming bluebonnet might not last long enough to even set seeds. If you do find some potted blooming plants, try to wait until the last minute to buy them, so they will last through your project on March 1. The rosettes you have might surprise you by starting to put on blooms sooner than you expect them, but they might not. It's colder in Amarillo than it is in the parts of Texas where the bluebonnets grow wild. All we know to do is wish you luck.
After this member of the Smarty Plants team published this answer, another member of the team with sharper eyes noted that Lupinus plattensis (Nebraska lupine) grows in Hartley County, Texas, near Potter County, as shown in this USDA Plant Profile Map. Lupinus plattensis (Nebraska lupine), like Lupinus texensis (Texas bluebonnet), is one of 5 or 6 members of the genus Lupinus considered the state flower of Texas. So, possibly that is what you are growing in Potter County, in which case they have a better chance of surviving. This lupinus is perennial. We have added a picture below of the Nebraska Lupine in case you feel that is what you are growing. Whether that would be the plant that is grown and sold in pots in Amarillo, if any, we have no idea.