New hire, can I request pay adjustment?

HELP. I am a new(er) LVN Graduated 04/2024, licensed 06/2024 and applied 07/2024.

I started at the VA on 01/2025 with Tele/SDU unit, they offered me a GS 3 step 4. While waiting for my start date I was able to work and gain experience. It was almost a full 6 months. Should I ask my manager about possibly increasing my Step from 3 to 4?

Also, how accurate is TXP? My salary is different from my offer letter. I am unable to check my paystub since I don’t have access to myPay yet. It was also mentioned that since I was hired within the 2.x% increase it should be reflected?

Thank you!