It's your choice alone and if you're feeling suicidal for whatever reason, that's totally fine. All reasons are valid, in my opinion, regardless of age, background and severity of struggles. It doesn't matter if you're simply tired of life, if you struggle financially, if you suffer from chronic pain, if you're haunted from mental illness or if you're in a constant state of loneliness. Maybe you suffer from all of these problems combined. These reasons can be medical, social or financial and they can be very diverse for all of us. They're different for all of us. They're all valid reasons and most importantly, if these reasons are strong enough to create a constant desire for eternal non-existence in you, in other words: you want to die, then that's totally valid in my opinion. If the idea of death outweights the reasons to continue living, then you already convinced the only person you must ever convince: yourself. And that's all you ever need to do. Like, I never talked to people in this forum and thought that their reasons to be here aren't valid enough. In fact, that just doesn't happen. Basically any person I met so far, in the 1.5 years I was active in this forum, convinced me that they're struggling from serious problems, worthly of an exit - and if that's their desire, they have every right to do so. My judgement doesn't matter. If you think you're suicidal, you answered your question around validity.
And that's the point of this forum: you are all welcome, no matter the circumstances or reasons that led you to this website.
It doesn't matter if you're a 25, 45 or 65 years old member. They might have different problems, but that's my point is: they're equally valid. I don't like the gate keeping that is sometimes practiced around suicide. There is already enough of that out there in the psychiatric system and in society in general, in one way or another. Like, either you don't get taken seriously by people and they dismiss you as an attention seeker or they take you so seriously to the point where you get locked up instantly in a psych ward, taking away all of your autonomy. Either way, it creates a stigma around suicide and it's harmful - the question of validity certainly plays into that sigma. It's also worth to mention that suicide shouldn't work like a competition, like certain struggles don't become valid just because they pass a certain pain "level" - because that's not measurable and comparable at all.
In my opinion, suicide shouldn't even be justified. Like, it would be totally fine if someone finds this forum, researches their method and simply heads out, without any explanation or defense at all - and I am sure that happened daily, since the forum was created. I think only a tiny minority of people actually stay around long enough to even talk about their problems. Most people just want to get it done and escape their pain. And justifying your exit simply isn't necessary because it would imply that life in general is worth living and that you need to somehow debunk this notion with arguments. It isn't and literally not one single person ever consented to their birth, that's something that gets overlooked every time we talk about suicide. So why should we justify our exit if we didn't even want to experience life in the first place. It just doesn't make sense and the question around validity doesn't address that either.