Yeah, I understand you, because many girls want to make their own eyes more beautiful. As a sister like you, I want to tell you there are two kinds of ways that can help you realize your dream. On one hand, you can depend on the makeup, for instance, you can use the eyeliner to make your eyes oval. As usual, you can try to add the black or brown line(pls note the color will depend on your hair color)at the top and bottom of your eyes. At the same time, you should also do a very very thin line on the eye lid, so does the bottom of your eyes. Do keep in ming that you had better buy the eyeliner with high quality, because the result will be better. On the other hand, you can ask your personal doctor do a plastic surgery on your eyes, which will cost you more. All in all, you should put your health at the first place.
You can achieve ovalish eyes by make-up. So, you shall first prepare eyeliner pencil, mascara cream as well as eye shadow. And to get a more ovalish look, you can choose smokey cat eyes. If you want to make up your eyes in this way and don't know how to start, you can search it on youtube videos where have many videos to teach you step by step. Good luck.
If you want to make your eyes look oval, you could use the eyeliner or other eye make up to get it. In addition, you could also use the colored contact lenses to make your eyes look oval. There are many colors of contact lenses. You could choose the favorite color to match with your clothing.