Rylee Arnold Gushes Over New USC Football Player BF, 'Loving Life Together'

Rylee Arnold's relationship with USC football player Walker Lyons is just days old ... but it's clearly going well -- as she tells TMZ Sports she's "loving life" with her new man!!

Arnold and Lyons went Instagram official shortly after the "Dancing With The Stars" pro caught one of his Trojans games last month ... and it's apparently been smooth sailing ever since -- as Arnold was nothing but smiles when talking about the guy this week.

While out running errands in Beverly Hills, Arnold told us she's "super happy" with her tight-end love interest ... and called their dynamic "really fun."

As for how they met, she explained the duo actually had a bunch of mutual friends who hooked them up.

"We're just having a good ol' time," the 19-year-old said. "We're super young -- so we're just loving life together."

She added, "He's just such an awesome guy."

Lyons -- a 6-foot-4, 235-pound true freshman -- clearly feels the same way ... as he posted a bunch of pics of the two looking loved up on his Instagram page earlier this week.