Moms not on board

Me and my so havent told anyone that we are ttc. However, my mom keeps giving me hints that she doesnt want to be a grandma yet. Her hints arent subtle, and i find them super offensive. Im almost 20, and have been with my so for 2 1/2 years. Should i take her hints with a grain of salt.? Or should i cave and talk to her about it. I dont want her to be mad, but i feel we are ready.