Rey David Herevia challenges his within-guidelines sentence of 57 months’ imprisonment, imposed following his guilty-plea conviction for illegally reentering the United States after having been removed following a conviction for an aggravated felony, in violation of 8 U.S.C. § 1326. Herevia claims his sentence was unreason *353 able both because of the age of the offense used to enhance his sentence and because of his assimilation in the United States. As a part of his written plea agreement, however, Herevia waived his right to appeal his sentence or the manner in which it was determined on any ground.

On appeal, Herevia does not challenge the validity of the appeal waiver, but instead contends that the Government has not adequately sought to enforce it. We disagree. The Government has asserted in its brief that it seeks enforcement of the waiver, and that it bars this appeal. See United States v. Story, 439 F.3d 226, 231 (5th Cir. 2006). Although a valid appeal waiver does not implicate our jurisdiction, see id. at 230, Herevia’s appeal of his sentence is clearly barred by the waiver.

DISMISSED.