Can I breastfeed both my toddler and newborn??

Hey Ladies!

This is my 2nd pregnancy and I found out I was pregnant way before my missed period. (Mother's intuition) I took a test and received a positive result. I am still currently breastfeeding my 1 and half year old, who is nowhere near ready to trade in mommy's chi chi's. I heard that my milk during pregnancy can change, and she might naturally repel from drinking it. Can I still breastfeed her and my newborn? If so, what steps should I take to ensure that they both get the nutrition that they need. She doesn't nurse often, mainly at night and during her nap times. I LOVE breastfeeding and have the flexibility to do so, I just want to make sure I can successfully feed both. (If you know of any gentle weening techniques, I would love to hear them!) Thanks ladies!! :)