As many as she will take, usually anywhere between 15 and 30 I believe. You will want to cut back on her feeding when she gets older to reduce the amount of eggs she will produce.
Also, a lot of great information can be found on the forums using the search function! If you type in key words like "juvenile feeding" or "female egg laying" into the search bar it will pull up all previous threads that included those topics. It's a really great way to study up and learn about the keeping of your new pet