I see that you're a new poster. Here's my advice. I see that you're looking for a hot 20 something Asian, aren't we all.
Obviously you were enticed by Mona's pictures. A Google image search reveal they are pictures of a Korean model, Huan Miao Mia. Secondly a Perb search of the last 4 digits of her phone number 6308 showed a couple of negative reviews of this micro.
Always do these searches when you see an ad that interests you, it is much quicker than waiting for someone to post a reply to you're questions. As an example the above took less than 10 minutes including reading the reviews.
My advice, you're new and looking for first experience, stay away unless you want to be adventurous and TOFFT.
As far as a 'real' 20 something, you cannot rely on reviews as age guesses are all over the map. As long as she 'looks' 20 something is all that matters. No pooner is looking at her birth certificate to get her actual age.
Remember reviews are just some other guy's opinion. They are not to be taken as gospel truth. Your opinion and experience may differ greatly.
I would recommend Adorable Vivi as a first experience. She's sweet and will make you feel comfortable. Search Perb for reviews she's one of the most reviewed girls in Perbian history.