You will get Legendary Items as drops as soon as you hit lvl 50. These are almost always 3rd age items, which actually is all you need until you hit lvl 100.
But. And.
The only way to get recipes to craft Legendary Items, be it level 60 or 100, is to join a guild.
Don’t buy all the recipes!
When you have the appropriate rep with the guild, you can buy Legendary recipes.
Do NOT buy them all (as I recommend that you do with the Improved recipes).
Only buy the ones you think you will need, as these recipes can be quite costly (the higher level ones cost 1 Gold 200 Silver each, and there are many).
I normally buy the 3rd age recipes (all levels) for the class I’m currently playing. I don’t bother with the 1st age (aka FA) recipes at all until lvl 100.

I only buy the lvl 65-95 FA age recipes if I happen to get the fancy ingredients needed and see a kinnie online that could benefit from this FA item – because I don’t need those fancy ingredients myself.

Because. Once again.
For your own account you can craft all but lvl 100 legendary items with UIP:s.
No shards, no mats, no fancy ingredients, no nothing else needed.
3rd age is good enough until lvl 100
You will level up just as fine with 3rd age Legendarys – the important thing is that you get to know what Legacies you use, as you will want those on your lvl 100 Legendary Items.
BTW. I rarely bother with slotting relics in my Legendarys until I have my FA lvl 100. Instead I use the Refine option at the Relic Master. It removes all pesky, space-consuming relics from my inventory (and LI screen) and turns them into shards. And shards (a lot of them…) can be used at the Relic Master to barter for Anfalas Scrolls of Empoverment.