There are indeed many cultivars of Crepe-myrtle. Some are selections of Lagerstroemia indica, but many newer cultivars are hybrids between the widespread L. indica and L. subcostata var. fauriei (or L. fauriei), a more cold-hardy and powdery mildew-resistant species native to certain islands in Japan. Lagerstroemia subcostata var. fauriei also has smoother, more ornamental bark and often passes this trait onto its progeny. Medium to large Crepe-myrtles are commercially available as both single-trunk and multi-trunk specimens.
Judging by the flower color, smooth patterned bark, and size, your specimen might be one of the following:
Lagerstroemia x 'Catawba', Lagerstroemia x 'Powhatan' or Lagerstroemia x 'Twilight'.
Lagerstroemia x 'Zuni' is another possibility, though it usually stays under twelve feet.
Flower color can vary due to lighting and camera settings so I tried to be flexible in judging the lavender-pink color shown.
There are other possible cultivars, but the ones listed above seem to dominate the market in their colour and size class.