How Long In Prison For Assault If Its Your First Offence?

The sentence for assault will vary depending on many factors such as the state that the offence was committed in and the severity of the assault.
Each state has their own laws which determines the punishments that come with a first assault and it will not always automatically result in a custodial sentence.
Background reports will look into the circumstances involved, if you are of good character and have references vouching for your previous good behavior this will have an impact on whether you receive a custodial sentence or not and also the severity of the sentence.
There are various degrees of assault, whether the victim is hospitalized or seriously injured will have a major impact on the sentence that you receive.
All sorts of circumstances will be looked into, the judge will want to find out if the assault was premeditated or whether there were mitigating circumstances that contributed to the assault taking place.
Speaking to a good lawyer that specializes in these type of charges will give you a good indicator to the level of punishment that you can expect.
A good lawyer will be able to highlight certain circumstances that contributed to the assault to show you in a better light. The more evidence that can be brought to bear for the defense, the lower the chance of a prison sentence.
However the prosecution will take the opposite view and will be out to paint you in the worst possible light. They will take the opposite view of your own lawyer and will push the judge to apply the maximum possible punishment.
Showing sympathy for your victim and outlining why it was out of character will help to reduce the potential sentence, if you show remorse and regret and have a good lawyer it may be possible to avoid a jail sentence.

For simple assault IV (FOUR) There would like be no jail time other that what you spent to be arranged.  Aggravated felony assault, bird of a different colored feather

I am getting charged with serious assault first offence with a bottle and permanent disfigurement but the person hit my girlfriend and attacked me but I hit him while he wis attacking but my friend battered him what do you all think I would get ? Still in school 16 years old first offence

That depend on the degree of the assault. Violence is bad and can be costly in the time department. Is it a felony?

You will prob get a warning once your under 18 or you cud b sent 2 a juvenile 4 a few days or  weeks wit a scare

Depends on what you did and your states laws. It can be anywhere from a week to a year probably.

Well you might get probation depending on the judge and how severe the assault may be. You can get defeered or suspended or go to the prison and come out on probation secondly .