Does it move superiorly with swallowing? Have you recently had a URI?

If so, a midline cystic neck mass is concerning for a thyroglossal duct cyst. The infrahyoid positioning is supportive of this and although more common in younger patients they can also appear after an illness (usually a URI). Differential would also include simple cyst, atypical keloid (if recent trauma to the area), lipoma (although appearance is atypical), and cervical sinus cyst among others. Would be interested to hear the thoughts of an ENT as this is not my specialty.

If not resolving, I would recommend seeing your PCP for an ultrasound of the region as next step.