Keep in mind that many of the "pretty" women that you see on TV and in magazines are created by makeup artists, hairstylists, and fashion designers, or by photographers generously using airbrushes.
I'm not a faithful reader of National Enquirer and other papers like it. But I love the way these papers show pictures of the "stars" without their makeup and without retouching.
Many of the "beauties" are actually rather plain. It's what they do with makeup, hairstyles, and fashion that makes them beautiful.
Digital TV has been a disaster for many women (and men, too)! Many of the "stars" and TV journalists look dreadful in digital--lots of wrinkles, age spots, bags under the eyes--we see it all clearly now! Shudder!
I'm guessing that if you were to spend the money on an "image maker" or "beauty consultant" or someone who can do a "makeover" on you, you would discover that you can be quite beautiful!
It might be worth doing that, just to prove it to yourself, and to learn to use makeup, hairstyles, and fashions in a way that will enhance what God has given you. You don't have to spend a lot of money. In fact, a Mary Kay consultant will do the makeup for free (although you will be strongly tempted to spend several hundred dollars on the Mary Kay products!).
I would also suggest that you keep yourself in good physical condition. There is something very attractive about a woman of any size or body build who is strong and in good shape. Do whatever exercise and diet program you like and works for you, but don't let your body get fat and flabby like so many women in the U.S. do.
My younger daughter is a beauty, at least when she has her makeup on and her hair fixed. She has participated in several beauty pageants and placed in the Top Three. People stare at her in restaurants and stores. Little girls on her skating teams constantly say how pretty she is.
But in the morning, when she doesn't have makeup on, she is not all that pretty. She has learned to use makeup to enhance her natural features. When you see her, you do not get the impression of caked-on makeup--in fact, you would swear that she isn't wearing any makeup. But she is! She wears a LOT of makeup! But she's very skillful at applying it so that it all appears natural.
My older daughter isn't exactly pretty, at least by the current "fashion world" definition of pretty. She has some facial asymmetry which could be very homely, and she also has smallish eyes. But she, too, has learned to use makeup, hairstyles, and fashions to create a very appealing "look" for herself. She wears certain pieces well, especially shawls and scarves, and she does amazing things with her makeup that enhance her faical bone structure and make her look extremely stylish and well-put-together. She is also in incredible physical condition and has a great body due to figure skating, marathon running, and yoga.
I would be careful about discerning a vocation to religious life based on your perception of your beauty. I'm guessing that you will be turned away, because a woman shouldn't join an order because she thinks she isn't pretty and no man will want her. You need to have a realistic self-image, not a skewed one based on observing other women and their "success" with dating.
BTW, it has been my observation that very few men ask a woman out. Most teenage boys, especially Christian boys, claim to be "too shy" to ask a girl out. I think that these "shy" boys deserve a good, swift kick by their parents! Boys who claim false shyness make it so hard for modest girls like yourself to find a mate without turning to coyness and flirting, and then the modest girls end up with losers who just wants sex. Good Christian boys need to gird up their loins, stop being wimpy, and ASK the sweet, modest girls out! Don't force them to flirt and be shameless just to get asked out for dinner!
Of course, the "courtship marriage" model that some extremely conservative Christians (Catholic and Protestant) are promoting is utterly ruining dating in the United States. No wonder boys don't ask a girl out on a date--they don't want the dad telling them that "my daughter will not date anyone until they are ready to MARRY her!" This is ridiculous and extremist and scares a lot of decent boys away. Why can't a good boy simply invite a good girl out for a burger and a coke and some nice conversation? The courtship marriage model is making it harder for boys to ask a girl out, and this is creating the feeling among modest girls that they will never find anyone to marry. So sad. I urge parents to please seriously re-consider if you are advocating the courtship dating model in your family. Talk to Christian parents who DO allow their children to date just for fun, and you'll see that normal dating isn't necessarily a pathway to sin. It's actually rather healthy.