This is an interesting question and one I've thought about a lot too. I'm 37 and an experienced developer/entrepreneur. I've been self-employed for 12+ years but if I ever had to "get a real job", it's something to think about.
First off, remember that it's not legal for a US employer to ask your age. They can only ask if you're over 18. Of course, if you want to be sly about it, you'll need to craft your resume carefully (putting the year you graduated from high-school or college can tip off). Also, your looks may or may not belie your age (I have no gray hair and can look late-20s if I shave my beard).
Also, I think the biggest (perceived) issues are that either (a) employers don't want to hire older developers because their experience demands higher pay or (b) they want younger developers who can work insane hours. I must say, I don't know if these are generally true (they aren't when I hire people).
But for you, (a) shouldn't be an issue. You're a new developer so you probably are fine with a entry-level salary.