She did understand why he wouldn't be sticking around and felt a surge of love for him for being so bold as to put his concerns on the back burner just to please her on her birthday. At the same time, Penny felt a bit guilty and hoped that his brothers didn't see him and totally ruin the peaceful and fun vibe of the party. Just in case, she turned slightly to check out who was around them and then focused her attention back on Percy.
"You're very sweet," Penny didn't miss his reddened face. "This really isn't my style, you know?" Of course he knew, but she still felt the need to explain herself. "Somehow Roger talked me into having this joint party and I don't even know more than half of the people here. It's a bit overwhelming." Penny glanced down at the ground for a moment, trying to remember her point and, finding it, continued on. "It's nice to see a familiar face."