Hi! Sometimes aggression is caused by a stressed beardie. Does your beardie have a proper
UVB light, proper basking/coolside temps, and is eating/pooping regularly? It's always good to check lots of beardie caresheets just to make sure! Here's a good one to start:
https://www.beardeddragon.org/articles/caresheet/
But sometimes baby beardies are just slow to warm up to human hands. How old is your beardie? Your beardie currently probably views your hands and your smell as threats, so it's important that they start associating those with food, safety, and comfort. Try hand-feeding your beardie some of their favorite feeders every day. Also, try putting your hand into their tank and just leaving it there for about ten minutes, then start moving your hand closer to your beardie every day: this will show your beardie that your hand is chill and isn't out to kill them. Lastly, try leaving a worn shirt in their favorite sleeping spot!
After you're able to pick them up, make sure you're holding them in a way that makes them feel secure and not like you're going to drop them. My beardie flips out if I'm not supporting all of her legs, her chest, and her tail. (Which is quite a handful--she's about 19 inches now!) The most important part of my beardie getting used to me was probably allowing her to roam about a beardie-proof room while I sat on the floor with my laptop. She would approach me, tongue hesitatingly licking, whenever she thought I wasn't looking. When my eyes locked with hers--she'd run away again! 8)