I would highly recommend using "tried and true" recipes first. You will find tons of them on this site in the recipe forum, and from numerous other places. Maybe even start out with some kits from LHBS/online vendors and use them as a jumping off platform to try to adjust your end product. If you are looking to improve your recipe formulation of certain styles, a book like "Brewing Classic Styles" is a great resource. Start simple, then as you get more comfortable, try experimenting.
In regards to your request for a fruit addition or fruit beer, I think several styles lend themselves well to fruit additions. The thing that's fun about this hobby is that you can really be creative. I've used berries in belgian beers, pumpkin/yam is great in ambers/porters, peach would be good in a pale or other light ale, cherries in a stout, wheats are great for fruit additions. I think there's even a commercially available onion porter from Hawaii! To add the fruit flavor, I like to use real fruit (fresh/frozen/canned) and typically use a secondary for about a week. Using citrus peel as a late addition to the boil is also a common way to go. Some people use flavored extracts before bottling with good results (never done this myself). I guess what I'm getting at is you have lots of options to explore!
For your son's first bday, if you're planning on sharing your brews with other party goers, I'd suggest something more in the main stream - perhaps a strawberry or cherry wheat/pale. Maybe even throw in a little vanilla if you live somewhere like me where its still likely 30*F in March. Good luck, and happy 1st bday to your son!