I'll answer but by no means am I in any position to be casting judgement or giving out criticsm.
I will start off by saying you definitely have a different look about you, big lips / wavy hair and nice shape to your eyebrows but it's hard for me to say more given the angle of that picture. maybe a front on picture would be better to upload.
You are very brave to post a picture up without any makeup on, I know heaps of girls who would die at the though of ever being seen by another person without being made up. You definitely have my respect for that.
If I was to be honest and that's what you asked for I would say you are a bit on the plain looking side but once again you may look totally different all made up but just judging by this picture that's what I would say. Your pretty but I'm not so sure about having a model look. Perhaps this photo doesn't do you justice though?
As far as being a model I have no idea what criteria modelling agencies go by in selecting their talent, you must remember a lot of cat walk models have a very unique look which may not fall in the publics traditional opinion on what is attractive or not. I think they look for big eyes, high cheek bones and and big lips usually, oh yes and height. I think its like 5'9 and up for women as the minimum reguirment.
But anyway I definitely would not say you are intimidating looking, you look like a nice person actually.
Good luck with your future modelling goals and remember only pursuit something if it's going to make you happy.
You are really pretty and physically I think you have what it takes. But, that is only the very basics of what it takes. I have only see two pics and my critique is to work on your facial expressions. On the last picture I think whoever took the picture did a great job of choosing where the light hits your face and where it doesn't. But, your smile is kind of crooked and it seems like in the shot you couldn't decide rather or not you were going to smile. Pay attention to stuff like that more. Because, pretty faces are a dime a dozen, but a face that really grabs attention is what model agencies are looking for.
You are cute, but you're too old to be a model. Most high fashion models get started at 12 and peak around 15/16. That being said,I can see you modeling looks in a hairstyle magazine or doing catalogue modeling.