is it aggressiveness?

Question
I just adopted a female English Bulldog from my local SPCA.  Overall she seems to be pretty well behaved, I have a Jack Russell that she pounces on every now and then.  My problem is I can't tell if she is aggressive or not.  I can't get her in her crate nor outside when I go to grab her collar to force her she appears to look like she is going to nip me.  She hasn't yet, because I hurry up and pull away out of fear.  I am not able to read her body language and can't tell if she is acting aggressively or not, and I certainly don't want to get bitten.  Can you offer me some advice?  Thanks

Answer
If she's not attacking the other dog, then it's not aggression. It's play. If she's not biting you, then she's not aggressive. If you're afraid of her, you will have a problem sooner or later.

When this occurs, take a rolled up newspaper and give her a couple of good whacks and a sharp "NO!".  I have a feeling she's just overly enthusiastic about having someone to play with.

I also suggest that you take the dog to obedience class so you both can establish your place in the house.