New to Touhou series, just started yesterday playing Double Dealing Characters.
Did you start playing DDC as your first game? If so, you don't need to play the PC-98 games first though, but I'd recommend you play atleast the first Windows game first, which is Embodiment of Scarlet Devil.
First stage: :3 Not as hard as others said~ No problem~
Second stage: Still manageable, lost one life
Third stage: WTF
Play on Normal a few times if you want. Then go straight to Hard/Lunatic.
Frankly in my first Touho game, which was EoSD. I improved on Hard, then after 1 cc in Hard, went on to Lunatic.
After that every succeeding game in the series was pretty easy on the first few levels in Hard and Lunatic. But I still will die in the games. I just try my hardest to get 1 cc.
If you think you can handle the stages on Hard and/or Lunatic, the problem only lies in the Bosses' spell card once you get the hang of it. It just requires some memory and prediction.
When I first play a new Touhou game now, I always start on Hard.
Only Touhou game I could never finish is the first one ever, which is Highly Responsive to Prayers. It's not like the Touhou you know, that's why it's hard.
If you want to have an easier play through. Use Reimu A or B. Either one's fine, since probably her unique feature, her small hitbox is what makes her rather easy to use, and can score some good Graze points.