I think it's awesome to want to get back into philosophy! I think it'll be important for you to really focus on why you want to pursue grad school and why you might not want to pursue it, especially given the emotional attachments you're likely to have to your options. Here's my limited view of your situation:
Good reason(s) to try to go:
You want to experience graduate study in philosophy
I think this may be basically the only really good reason to apply to grad school. As your posts above suggested, however, this can be a weighty consideration. There are things you just want to study, learn, and write about in an intense way that can't be replicated by treating philosophy as a hobby. This is the reason that has motivated me to pursue a graduate career and I will happily defend its weightiness!
Bad reason(s) to try to go:
You want to get a job in professional philosophy
This is just not a good reason to go to grad school anymore. While we can all aim to get one of these coveted positions, as my undergrad adviser once said, "only go to grad school if you would still go if you knew ahead of time that you would have to do something else if you graduate." It seems like you're up for that, but it should be noted.
It's what you've always planned on or imagined doing
I tend to think this is just not a good form for a reason in general. Independent of other considerations, such as reasons that following the plan is a good idea, one's planning to do X is just not a reason to do X. I do think this is a pretty prominent psychological tendency however, so it's something to look out for. Just because past you thought you'd be in grad school by now doesn't mean present you should go.
You experience regret about past events that prevented you from going to grad school or nostalgia for your younger aspirations
This is a really relatable emotion, and I frequently find myself thinking that I can somehow undo or make up for past decisions if I do something different now. But once you spell out that that's why you want to do something, it isn't hard to see that that's not really a rational way to make life choices.
Good reason(s) not to try to go:
Grad school would expose you to unacceptable risks
Grad school can produce horrible career outcomes, life outcomes, etc. as people often discuss on this forum. While this is true for all applicants, a person's risk profile often does change with age. With respect to this decision, for example, a younger person might be able to begin a second career and still save substantially for a retirement if his or her philosophy plans go belly up. This might be substantially harder for an older person, who may also face a different set of options for an alternative career.
This consideration will vary depending on what your options will be if everything goes wrong, of course. If you're really confident you could resume your old career after a decade (give or take) doing philosophy, then maybe that assuages the worries to some degree.
Bad reason(s) not to try to go:
You worry that you won't fit in/your age will make it harder to network
This isn't a formally bad reason, I just don't think it's very likely to be a problem. A lot of people in graduate programs are older, at least by the end of their programs (I'll be 32 if I graduate in 6 years) so it's not like professors always deal with students in their twenties. I think your fellow students and professors will be happy to hear what you have to say and engage with you without problems. And even if there was some friction, I'm not sure that would be a decisive reason not to study what you want to study.
You worry that you won't be seen as a serious candidate
I'm not sure why this would be a reason not to try. If you're willing to risk the years of opportunity cost that go along with graduate study (along with everything else), why not risk a few hundred bucks to see if some programs might be interested? If this was a point about job market competitiveness, I would refer you to the point above about why wanting to get a philosophy job isn't a good enough reason to try to go to graduate school.
You are anxious/embarrassed etc. about being a nontraditional applicant
I'm not sure if this is something that you're feeling, but it's another very relatable emotion that might be involved in a choice like this. I get nervous going to shoot some basketball at the park because I'm bad and the part of my brain that enables me to survive as a social animal gives me a talking to about deviating from norms in public. This is, of course, a great strategy for never playing any basketball, and I have to resist this impulse if I want to grow and enjoy my hobby. I feel the same way about your kind of choice. It might feel like grad school is somehow "not for you" because your path was a little different, but that's not a feeling that's really tracking anything important about the situation. If it's what you really love, do it, even if it feels weird.
How you balance these things will have to be up to you, but I think those are the reasons I would be weighing in your position.
