I am worried about the size of my double bass...

I have been playing double bass for roughly three and a half years. This bass I am using is borrowed and it is a 2/4 size. My teacher told me my first finger should be at eye level. I can pull my endpin all the way out and my first finger is too low. Should I go up to a 3/4 size or stay? And if I need to get a new one what is a good price?
 
OP,

By high school, most Double Bass players are playing on a 3/4-size.

So, unless you are under 5' in height, you may want to move up to a 3/4. By the way, there are plenty of small-sized human beingss playing on a 3/4-size bass.

Can't help you with the price since the sky is the limit on what one can spend on a Double Bass.

I'm sure the experts will be chiming in, shortly.
 
I am so sorry for the delay in replying. A glitch that prevented me from receiving notices of postings and then being able to reply to them has just been fixed.
The majority of bassists including myself play a 3/4 size bass. I agree with your teacher that it is time to move up to a larger instrument. There are good basses available at prices from around $2,000 and on up. There are several respected upright specialty shops around the USA that will help you with your selection. It is not usually recommended to buy an upright from your local guitar store. Your teacher can probably give you some guidance to a place near you.