Help with a difficult Stimmie?

My pet stimsons python has been really aggresisve lately. Its a female about 115cm long and she is really aggressive whenever i try to pick her up (note I haven't handled her in ages). This is what I usually do when i try to pick her up. I open her cage door, and let her head and like half her body come out. Then I lift her up from her belly, but her tail hold on to the cage/ objects in the cage. So then I put her down and she goes back into her hide. She then comes back out after a few minutes and then I offer her to come out again. She just opens her mouth which I assume means she is angry or scared so I leave her alone. Tips on how to let her let me hold her would be useful. Thankyou for all answers!

P.S It's summer here in Western Australia about 35 degrees Celcius so I'm guessing that makes her more active, but agressive too?