I've caught up on this thread, and I really want to post to say that I did not have the experience that some of the other posters had in terms of age affecting hiring. I did far better than my grades would have indicated -- even taking into account my IP goals. I do agree that IP boutiques in particular do have lots of people with advanced degrees and work experience, and culturally might be a better fit for someone who is an older grad and wants to be in a more family-oriented and accommodating firm. But, I saw pretty good outcomes with the big generalists that were more my target & never got the feel that they were hesitant about the way that I would fit in. At the same time, yeah, I wasn't in the ballgame for the real elitist grinders, i.e. V5, but certainly V10 on down I didn't encounter much skepticism.
At the end of the day it comes down to what school you went to, what you have in terms of experience if it's relevant (i.e. finance, business, engineering), grades do matter if you're targeting elite firms from top schools or BigLaw generally from the rest, and then the interview matters. In particular, you are evaluated heavily on the kind of questions you ask and the discussion that results from the interviews you have.
As I think I advised upthread & is mentioned in an outstanding post re: OCI prep that's also on this thread, there are a lot of opportunities as a 1L (assuming you go to a BigLaw feeder) to meet with people working at those firms, interacting with associates and partners who were older law school grads, and really getting a feel for (a) is this work you want to do, (b) what it's like to be older than the average junior associate, and (c) the advantages of being older. And, yes, there are advantages. There are all these horror stories of 25 year old first year associates acting unprofessionally, and there's just generally this learning curve towards being an adult, with a job, and taking on responsibility -- which doesn't apply to us. Firms do seem to recognize this. Or, they lied? -- but they did extend offers to me, as well as the other "non-trads" at my school (both IP and non-IP).
The key is to figure out how to present yourself in an interview so you don't seem arrogant, you want to learn about the law firm practice, and you're enthusiastic about wanting to work there. And, frankly, if you really don't want to be in that position, don't do it, and if it means that financially law school doesn't make sense (i.e. because you don't want to do the LRAP at this stage in your life or don't have enough saved up or a spouse who can support you) then don't go. Even if you're going debt-free to some local T3, there's still significant opportunity cost.
I think this post maybe comes off a little strongly -- we all have our own experiences and anecdotal data, and a lot is influenced by our own personal backgrounds, the markets we target, and what law school we attend.