Setting boundaries

Christina
My boyfriend & I have been living with his parents while we're in college, it's been great! They're very sweet, and generous people. 
However we had an unplanned pregnancy occur & while they are beyond thrilled for their first grand baby, I couldn't be more nervous. His mother especially is EXTREMELY eager to be a grandmother. While I definitely love that she's so excited, and that my daughter will be surrounded by so much love, I'm just very apprehensive. 
She keeps referring to my baby, as 'her baby', continues to make comments to me saying 'hurry up and give me my baby!', 'Once you guys move out your daughter will miss you!', 'you can hold the baby sometimes, but I will hold her the most!' & other things like that. She also bought her own running stroller/baby monitor for herself for Christmas. (She wants to take the baby on trails, camping trips and what not, & she wants to know anytime the baby cries so she can come and take her), she keeps making all these plans with my daughter. 
It's really overwhelming me, especially since I haven't even given birth to her yet! I really just want her to back off a little. I know that she is just excited, and I'm not entirely sure how serious she is about some the the comments she makes, but as a new mom it's sort of upsetting me. Right now, I can't imagine anyone other than my boyfriend taking her.
My boyfriend and I have already discussed with each other that we want the same respect that any other parent who lives on their own receives when it comes to having a baby. I just have no idea how to go about implementing this without hurting any feelings. Any advice would be much appreciated!