Congratulations! :) I have two younger sisters (and am a woman myself). Imagine, THREE girls, currently aged 18-27.
Our mom was definitely an important role model for us, and she never really paid mind to traditional gender roles (though she did end up kind of following many of them...). As a kid/teen in a rural village in Russia, she learned to sew and knit and cook and work in the garden and can/preserve, but also to split wood and drive a truck. She then went to the premier science and technology university for a major that was maybe 10% women and did many outdoor adventure sports (XC skiing, kayaking, mountaineering). When we were growing up, she couldn't work due to visa status and was a SAHM for us, so she did take on many traditional aspects of that role (cooking, cleaning, laundry, etc) but she also managed to read for fun (by herself, not just to us!), took some classes in various computer subjects and English, and was usually game to take something apart and try to fix it if it broke--she was more the DIY person than my dad. She and my dad took us all out camping and hiking early and often, or sometimes would trade babysitting with friends and go for a 20-miler by themselves. Anyway, being raised by her, my sisters and I aren't particularly girly (don't wear makeup, pink, frills, rarely dresses, etc), we like long walks/exploring on foot (two of us like the outdoors, youngest sister prefers cities), we aren't fans of team sports, we love reading and learning new skills, we aren't afraid to get our hands dirty, and we (still) think bugs are "cute". Except giant cockroaches. But for all those similarities, we had/have entirely different college majors and career interests, we had different extracurriculars (due to both circumstance, i.e. parents' financial situation, and interests), we had varying degrees of interest in fashion/appearance (all higher than my mom's, see: peer pressure).
Let your kids develop their own selves--sometimes, the younger sister may want to be like the older one, but sometimes she may want to set herself apart. Comparisons are often hurtful...and that goes both ways. Model and encourage the behaviors/attitudes you want. Go camping as a family (my trainer once shared that her husband took her sons camping while she and her 5yo daughter had a "girls' night in" and painted nails and played Barbies...NO! Take the Barbies camping! Paint nails another night!) If you want your girls to be bold, not squeamish or fragile, don't chastise them for getting dirty or ripping clothes, laugh it off or praise the action that led to it instead, and applaud it if they overcome fear or disgust to hold the daddy long legs or pet the snake at the zoo or clean the toilet the first time. Praise their effort, not their skill, to build a 'growth' mindset and make them more resilient:
https://www.psychologytoday.com/blog/the-science-success/201101/the-trouble-bright-girls.
About relationships/dating...the best thing you can do to ensure their safety and happiness is empower them. Rules are meant to be broken, but personal convictions are something else entirely. When I asked my mom if I could go on my first official date, her response was "well do you want to?" (I did. I went. He was my first love and we dated 8 or 9 months.) I have a hard time saying how exactly the empowerment worked...I know by 16 I had a good idea of what a healthy, respectful relationship looks like, the risks of sex, the ability to say "no" and set boundaries, and the sense that I didn't really need a boyfriend (though having one was mighty nice). Except none of this was really explicitly hashed out, outside of my mom once telling me (paraphrased) that boys kind of lose their heads when they get to close and it was up to me to stay in control of the situation. The only other thing that maybe played into it was being talked into trying new foods, watch certain movies, etc. and being allowed to argue/refuse. Once you can say no to your parents who are trying to make you do something, you can say no to basically anybody. At least, in my case. (Note: asserting yourself and throwing a fit are very different behaviors though.)
As far as advice on raising smart, strong, independent women generally, I would recommend
http://www.amightygirl.com/. I follow their facebook page and they constantly (daily) have posts about women of great character and accomplishments, both historical and contemporary, both well-known and obscure. They also have some good book recommendations; I got a back-to-school one for my friend's son and it went over great.
Also as far as books: slip them some Tamora Pierce when they are 10-11 or so. Girls becoming knights, fighting bandits and monsters, magic, talking animals, dragons, princesses that kick butt. Touches on friendship, bullying, leadership, and a much healthier outlook on love and relationships than Twilight, or other YA romance. I'm mostly going off the five series that take place in one of her worlds; there's two or three other series she has that I'm less familiar with; but I'm sure the themes are similar. The reason I recommend this is that I had a lot of fun reading them, and didn't realize until grad school that they had built up in me a sense of "I can do anything I set my mind to" that I fell back on when going got tough (grad school was probably the first time the going DID get tough in anything I felt mattered).
Again, congratulations! You'll have fun!
