My sister sometimes thinks I'm immature and she's 22 and I'm 19. Sometimes there're things I feel that I'm more mature than my boyfriend and he's only 2 months younger than me. The conclusion is, at this phase of becoming an adult and properly growing up, even one year is a huge difference in growth and maturity. Unless you're exceptionally mature for your age, I think it might be wisest to go for girls more your age. Cus you're 17 - you don't wanna be settling down yet, I assume, and you probably don't have much of an idea as to what to do with your future. That 23-year-old woman - she probably has a job and is looking to settle down within the next few years and will start to know what she wants from her life. I'm just saying - 5 years is not a lot but when your goals and thoughts and things that matter to you two are so different, it's gonna be hard to make it work. You're gonna be worrying about applying for universities while she will be worried about whether she would get this job or not. You're looking into campuses while she's looking into houses or flats.
Basically, it could work, but it might be wiser to go for someone more in your stage of life - eg, a girl between 16-19.
Good luck xx