Your periods may appear normal, but it does't mean that your entire cycle (including ovulation) is without having more detailed information.
Normal cycles can range anywhere from around 24 - 33 days or more. Ovulation does not occur on day 14 for everyone, even if your cycles are 28 days. There are 3 primary ways to recognize ovulation including basal body tempratures, cervical fluids, and cervix positions. Do you know how to recognize any of these? A book I recommend to everyone is "Taking Charge of Your Fertility" by Toni Weschler. It can explain what I mentioned above.
Also, as J_9 mentioned, healthy couples can take up to a year to conceive. Once you get to a year with no result, you and your partner should see a doctor for a fertility exam. Those prenatals are a must have as well. Spina Bifida prevention for your future baby is one good reason to take them. :)