I am a new photographer and not sure what to charge people?

Hello! I am 17 and have begun to do photography pretty seriously. I have a photography page on facebook, and as a result, I have friends and other people ask how much I charge per shoot. I don’t want to charge a lot just yet, but quite honestly I am not sure what is considered a lot in this field. A kid I know in my town who is 15 charges around $50 per shoot, but because of this he was able to buy the equipment-a mac, photoshop, etc to progress his business. What would you suggest I charge? Around $25-$30? Is that too much or too little for, say for example, senior portraits?