So you are still a virgin? What makes you think it's too small? Have you tried to have sex and just couldn't get it in or are you just basing this off of your own private experimenting?
If you are still a virgin, keep in mind that women are always tight for their first few times or so. It is so tight that it is uncomfortable for many women when first inserting the penis. It hurts many women due to the stretching. That is all very normal and is just something you have to work through.
Also remember that if you penetrate yourself with things, you may lose your virginity without ever having a man inside you. The first man you are with will likely take pride in being the one to take your virginity. Men know to expect virgins to be extra tight so he should not be surprised. It takes time and patience to work the penis in and many people have to try multiple times before they can get it all the way in.
If you still want to make it wider, then the best way to do that is by masterbating regularly with penis-like vibrators. Start out with something that fits nicely and buy new vibrators which gradually increase in size. The vaginal opening will start to open up. However, you have to keep up the masterbation or start having sex because when women go long periods without sex, the vagina has been known to shrink back up either slightly or back to it's original size.