Coukd i drop the charges on my bf even though im 15

Because you are a minor, you will not have the ability to "drop" the charges.  Your parents together with you may be able to talk with the prosecutors and explain to them that you do not wish to testify against your boyfriend.  Nevertheless, the law allows the State of Texas to still bring a case against him.  Even if you were an adult, the State of Texas and the prosecutors ultimately can still bring the case against your boyfriend.  The trial lawyer representing your boyfriend should know what to do in this case.  You should also make sure that you are safe.  You should do what you can to get good counsel on how to proceed to look out for yourself and keep yourself safe at all times. Your boyfriend needs to retain a lawyer who knows how to represent him in these types of cases.