I mean this is definitely a difficult decision and you are right, but so is your grandmother. That's what makes it so hard to decide, I think, as there are equal pros and cons. I'll tell you my battle in that walk of life to see if it gives you any insight. I had never in my life met a thumb sucker until my own daughter was born 8 years ago. She came out sucking her thumb, and never once would take a pacifier to save her life. She was exclusively breastfed the first 2 weeks of life, but then I had to switch to forumla and bottles. the way she was fed mattered not, she refused the binki profusely. EVERYONE constantly told me not to let her do that and to do everything in my power to make her take the pacifier as they said, "you can throw away a paci, you can't throw away her thumbs." I tried to take that advice for 2 months but finally gave in to her thumb sucking ways, as mama and baby had barely any sleep due to the battle of the thumb. I told everyone I did not care what they said, she wouldn't take a binki and she needed her thumb to cope and self soothe sometimes. I told them we would cross the bridge of breaking the habit when we came to it a few years in the future.......lololol she is 8 yrs old now and still sucking her thumb. Do I regret letting my newborn form her thumb sucking habit she was seemingly born with? No, because it allowed her coping mechanisms and the ability to self soothe the same as a pacifier or a blankie would do. Am I sad that she still sucks her thumb? Yes, it has messed up her pallet/front teeth shape and sometimes kids make fun of her. If another one of my children sucked their thumb as a baby would I do it again? See, IDK. I want to say no because I have "learned my lesson," but I also want to say yes, because it helped me and her to get sleep and comfort at times when she normally would've used a pacifier. If we had fought and eventually gotten her to take a paci would she have just used her thumb once we threw them away? That is a good question that I will never know the answer to but would love to. Idk if anything I said helps, but just know either way, mama, you will make a good decision to protect your baby to the best of your ability. As parents, all we can do is the best we can to love, protect, support and comfort our babies.....even if that means making mistakes along the way.