my puppy wont take a walk with me solo but will with my girlfriend why?

Dogs can be such interesting creatures. There are a few possibilities off the top of my head. First, it's possible she just enjoys walks with your girlfriend more, either because she's more bonded to your gf or because the walks are actually different (different pace, different route, difference in who's in charge compared to walking with you, etc.). Another thought I had is that you feel differently outside than your gf does - maybe you prefer being inside, get anxious, frustrated, bored, etc. Dogs are very good at picking up how we're feeling, so it's quite possible your pup is saying "hey, if you don't wanna go, I'm not going either!" On the other hand, your gf may be excited, happy, or eager to go for walks, and your pup picks up on that, too. It's also possible your pup is a bit anxious about leaving her "mom" behind or possessive of your gf, in which case it's good for her to practice being away from your gf. I'm curious if she tends to follow your gf around the house, whine when she's away, growl when you come near her, or hover outside the door when your gf goes to the bathroom.
Here are some ideas to move forward:

1. Take a different route.
2. Practice walking on leash in the yard. Treat and praise her for moving with you, and be super excited! If she doesn't walk in the yard, try just playing with her while she's on a leash - let it drag on the ground or hold it while you play together.
3. The next time she stops moving forward on a walk, note your emotional reaction. If you're frustrated, assume your pup picks up on that. Stand there for a minute to collect yourself and try to get into a happier, eager mood.
4. Try coaxing her with treats or bouncing a ball in front of her - any movement that's not backwards is good at this point. Be super excited, say "come on girl!", pat your legs, make kissie noises, all that. In fact...
5. Give her a treat, lots of praise, excitement, etc just for leaving the house with you. Demonstrate that going out the door with you is awesome!
6. When she stops, walk back next to her and start jogging in place and acting super excited.
7. Try putting some consistent, gentle pressure on the leash for about 30 seconds - not to drag her, but to see if she's willing to give it up and keep moving forward. Pull just "hard" enough (not hard at all) until you see her head start to pull back, hold for 30 seconds, and release if she doesn't move forward. While you're doing this, act excited, call her name happily, say stuff like "come on sweetie!", pat your legs, and make kissie sounds.
8. Get a flirt pole, lol. Think carrot on a stick.

I hope this was helpful ... (more)