Help needed

Hi there , I'm hoping you'll be able to help me , I purchased a 15 week bearded dragon 2 weeks ago , when I was in the shop I was able to hold her but since bringing her home she has scurried away from me every time I have opened the tank , then over the last two or three days I have slowly put my hand in the tank and she has literally hissed at me each time , I'm so upset as she is obviously unhappy in her new home , and am I right in thinking the longer you leave it to handle her the less chance you will ever be able to handle her ? And what happens when it comes to clean the tank completely ? So confused , any advice I would be so grateful for

Welcome to the forums!
I understand the concern regarding behavior. I am unsure if a mod wants to relocate this from ER to behavior.

At the pet store she was likely comfortable and used to her surroundings. Being only a couple weeks in she's probably just afraid. Everything looks, smells, and tastes different.

I'd give her some time to settle in and try handling her more around night time when she's less active. If she continues to hiss, go in with tough love. Glove up in case of biting, and continue to approach your hand to her. Don't chase or stress, but hold your ground.

Have you tried feeding her by hand? If you approach her with food, she'll start to associate your hand with nummies rather than fear.

Personally both of my dragons were rather tame, but my now oldest did hit a spurt where she got moody and would hide behind her plant and puff when I went to get her, around 6mo old, but I just continued handling her anyway and she calmed down.