Brooke Mueller Gushes Over Charlie Sheen
07/18/2007 AT 04:05 PM EDT
"I definitely want a big wedding," Mueller, 29, tells PEOPLE, "but Charlie and I haven't planned anything yet."
The couple are in no hurry to tie the knot. "We just got engaged and both of us want to enjoy the journey right now," says Mueller. "We really want to live this part of our lives."
Last month, Sheen, 41, proposed to Mueller, a real-estate investor, with an 11-carat, nearly $500,000 engagement ring during their 10-day vacation at the Four Seasons Hotel in Costa Rica.
"I was totally caught off guard when he popped the question!" Mueller says. "We were having a romantic dinner in the hotel room with room service when he asked me to marry him. I was thrilled. I smiled all night and kept looking at the ring because it was so beautiful."
As for what attracted her to the 41-year-old star of Two and a Half Men, Mueller – who was introduced to Sheen by her best friend, Rebecca Gayheart, at a party in April 2006 – says, "Charlie is brilliant and has the most captivating mind of anyone I know. He makes me laugh all of the time, and his witty one-liners are relentless. He is simply charming."
Being engaged to him is different than just being his girlfriend, she says, explaining, "Although everything is the same between us, I feel more part of the family now."
Speaking of which, Mueller is already close with Sheen's two daughters, Lola, 2, and Sam, 3, by his former wife, Denise Richards – who has sent her best wishes to the couple.
"I adore both of them and see them often," says Mueller.
Reporting by LINDA MARX