Just throwing it out there: you can contribute to legendary R10s on a 1st life toon.
It's very much like Ying pointed out: if you want to start running reapers - you can start running reapers. If you want to start running raids - you can start running raids. Sometimes these things are just a question away: hey, i'm a low-PL/no gear player, how can i contribute in reaper/raid groups?
Build a tank. Every raid group wants a tank. A 1st life tank in feywild + chrono gear is very capable of even r1 raids. How do I know? We ran a mid-reaper 6-man PN with a 1st life tank doing just that.
Build a favored soul healer. Again, every raid will want a healer. First life FVS with NO RAID GEAR can get about 3k+ hp and around 600+ positive spellpower. How do I know? I made one for LD's 1st life raid challenge before they moved to Argo.
Build a ranged dps. You want to dps, but not be a soulstone most of the time? Go ranged. Let your melees pull aggro, then shoot what they're smacking. You're contributing, but generally staying out of harm's way.
Leave instakills for a bit later. While DPS can contribute even undergeared (just with a lot less effectiveness), instakilling is an all or nothing game. The mob either died or not. This requires you to be a bit more geared, have some PLs. But it's definitely doable even on non-completionist toons. And a lot easier to do on lower reaper difficulty.
If you're trying to run higher difficulty reaper - be prepared to die. It's not a question of if, but when and how often. Everybody dies on R10. Even the best of the best who can solo R10s on a good day. An invisible vengie circle, a missed fear reaper, a bad reaper spawn, poor dice rolls. Don't be afraid of failing. Just learn from mistakes.
Identify easier quests to bump up difficulty. As someone already pointed out - older content is often easier due to power creep. So maybe go a bit spicier than you usually run. If you run mostly elite - run Gianthold walkups on R1. It'll be a bit slower, you won't earn obnoxious amounts of RXP. You'd be surprised at how quickly you will accumulate RXP just slightly pushing the difficulty from R1 to R3/R4. You still won't see any of the advanced reapers. And the jump in RXP payout is much larger than the difficulty jump.
On the opposite hand: don't worry about lowering the difficulty of harder quests. Newer content is usually more difficult. And some quests in particular are more difficult than others. The game is a marathon (unless you want it to be a sprint). Don't assume that the only way to earn reaper points is through R10s.
Ask questions. There's plenty people on these forums who are very experienced in the game. Just from this thread I can name you 2 people that I've ran with personally, who are VERY good at this. And there's plenty others who I don't know. We all started at 0, just like you. We know what you're going through.
I might get some flak for this. But if you don't want to group up - bring a hireling. A healer hire will do wonders for helping you survive your initial foray into low reaper content. But grouping is obviously more efficient.
Maybe get a few important PLs before you dive in. Paladin, Barbarian and Ancient Blessing PLs can benefit any build.
In a similar fashion, a good race can help out a lot. While warforged have some nice immunities, they're not as easy to heal. On the other hand something like human will give you a free feat at level 1, and 20 healamp for 3 APs spent in racial tree.
Last but not least: don't be pressured into doing what you don't want to do. Play at your own pace. At the end of the day we all play DDO to have fun. For some of us fun is in the challenge of hardcore server, or r10s. For others it's all about raids. And yet for some a casual stroll through "hard" after a stressful day at work hits just the right spot.