By Steve Helling

03/23/2013 at 04:00 PM EDT

To be sure, of all the invitations that Kate Upton has received in the past year, none has been more memorable than the Los Angeles teen’s playful video asking her to the prom.

“It was so flattering,” Upton, 20, tells PEOPLE. “The video was so cute, and I really appreciated it. There was something about it that I knew I had to respond.”

And good news for Davidson: he displayed a character trait that Upton likes.

“When a guy has a good sense of humor and confidence, that’s attractive,” she says. “This video was creative and funny. It made me laugh, and everyone loves a good laugh!

But … with modeling, acting and charitable obligations on the horizon, Upton says that her schedule is packed for May, the month of Davidson’s prom.

“I’m not sure if I’ll be able to go with him or not, due to my schedule,” she says. “I want to, but I just don’t know if I can make it work. But I really appreciated being asked; it made me feel really great!”

If she were to ultimately accept his invitation, Upton would have to go shopping.

“I feel like the best part of prom is picking out the dress, it’s probably not actually the dance itself,” she says. “I wore a very simple dress to my own prom; you don’t want [to wear] something you’ll regret. It was purple, and I loved it. And that was the best part of the whole thing! As for the prom itself, I don’t remember it being anything more than any other school dance.”

On Friday, Upton showed how full her schedule is. She spent the morning at the Arnold Palmer Medical Center, touring the facilities and meeting ill children in the Center for Children’s Cancer and Blood Disorders. After meeting with cancer patients – including a very excited teenage boy – she told PEOPLE about the perspective she’s learned.

“I’m a model,” she says. “I don’t cure cancer like these doctors do. So I need to use what I have to give back,” she says. “There is no question that I have been blessed – incredibly blessed – and I want to find ways to help others. I’m open to doing any sort of charity work, but I have a special place in my heart for children and animals.”