1. thats disgusting.
2. what does your age matter?
Start with your finger.
As long as you are still pretty new at it, I think you should just stick to lubed up fingers. Don't make any sudden movements and go slowly until you know what you're doing.
a finger lubed up with Vaseline
also heres an article from wikiafterdark.com
The prostate is often referred to as the male g-spot. When starting out, it is best to use a well lubricated finger or small dildo into the anus. Begin by massaging the area around the anus, especially directly below the anus. This area can not only feel great but also help relax the sphincter muscles. Begin by inserting the pad of your finger instead of the tip to avoid scratching by your nails (please be sure to cut and file your nails to avoid scratches) and pushing out with your sphincter, this allows your finger to slide in far more easily. Once you have inserted a finger to approximately the second knuckle, make a "come hither" motion (similar to that of the motion one makes when attempting to stimulate the female g-spot) towards the base of the testicles. Chances are you will not have trouble finding it, although it may take some searching. Once found you can experiment with different ways to stimulate, some like direct constant pressure, while others enjoy on and off pressure, or vibrations.  While this may feel strange or uncomfortable at first, when done correctly, it can often lead to intense pleasure for the male. Some males are able to orgasm with prostate stimulation alone, while others need their penis stimulated to ejaculate.
Finger, toothbrush, candle
i started with my finger. i have used different things, it is not dangerous if you use plenty of lube an dont rush it. the thing that i liked most was a banana....with the peeling on of course