If this is serious thread, I'm just letting you know that it's not going to be a good experience. If she's not actually interested in doing it, her body will be tense and it's going to hurt her a lot no matter how much lube you use. She needs to be extremely turned on and 100% submitting physically and emotionally to you so her body will relax.
You've been begging her for a month straight to do this. She doesn't actually want to.
If it hurts for her she's going to be even more reluctant to try it again in the future and she will be insecure that she couldn't satisfy you