career advise needed *urgent*

Recently I changed jobs and came to work for my current employer. I’m 21 and I have been working professionally in the IT field for 4 years. I was hired on here at an entry level position. Recently I discovered that there are more then a few people I work with without any prior expierience who are making more than I do. I’ve only been at my current job for 90 days and I’m not sure how to approach my manager to discuss this. Its not that I think I believe I deserve more money but I do feel that I deserve to make what the other entry level employees are. I could really use some advise on how to handle this situation.