I had teachers. You absolutely HAVE to have a teacher; there are subtleties to it that are at best difficult, if not impossible, to get from a book and there are mistakes a non-piper simply won't hear. I have never heard a self-taught piper that wasn't a bit of an embarrassment.
How hard? A lot of training required in some areas, others are easy. For one thing: 9 notes only, no sharps or flats. Now I'm talking the Great Highland Bagpipe here, not one of the dozens of other lesser-known varieties.
The areas of difficulty:
becoming quick with gracenotes,Tuning: a bagpipe has three single-reed (think clarinet) pipes and one double-reed (like oboe). Cane reeds are rather finicky, like herding cats, and take a lot of work to play stably. A long parade under a hot sun is guaranteed to have you a bit out of tune at the end.
getting the "ornamentation" (runs of gracenotes) right,
physical effort (about a month and you're past that -- left arm, lips and diaphragm),
bagpipe maintenance (with many plastic parts a lot easier today, though I like the tone of cane reeds better),
memorizing whole tunes (you never perform from sheet music),
dedication (pipes NEED to be played 1/2 hour every other day at worst, an hour a day is better -- with new materials this may have changed),
and tuning.
In solo competition, before the piper plays his tune(s) he re-tunes his pipes, right in front of the judge. Twice in my competition career I struck up the pipes and they were in perfect tune -- something few pipers experience. I did that in my very first solo competition, in a hall filled with pipers who knew much than I -- believe me, they noticed! And my teacher was SO proud... but it was luck.
The first step is to find a teacher. Most pipe bands teach, and some solo pipers teach as well. Any piper should know who's teaching. (Good news is that pipe lessons tend to be much less expensive than other instruments.)
The teacher will guide you on the book to use, and on the purchase of a practice chanter, probably $40 - $100 today. (It is a small, quiet version of the pipe chanter.) Most students are ready for the pipes after 6 months to a year; that's a bigger investment, I am guessing $1000 to $2000 today. I don't know the best brands today.
If you learn from a band you will learn the band style -- precise timing, unison playing, marching, parades, parties, having the ladies admire you (if you're a guy), etc. It's a lot of fun.
A solo teacher may teach you a different style, more traditionally Gaelic, in which you throw away the rigid timing. The ONLY avenue for expression you have is in the timing: pitch and volume are fixed. I learned from solo teachers and usually got high marks for expression. It's surprising what a difference it makes -- a well-played "Lasan Phadruig Caogach" ("A Flame of Wrath") will send shivers down your spine. Especially when you know the story.
Oh yes. Music. There's the "ceol beag" (small music) you'll start out with: slow airs, marches, strathspeys, reels and jigs. You need a solo teacher to venture into the realm most pipers don't go, the "ceol mor" (great music -- the classical music of the pipes) a.k.a. piobaireachd (English: pibroch).
"A Flame of Wrath" is a piobaireachd; these are works of art featuring memorization (the longest go to 45 minutes or so), played strictly from memory (it's not as bad as it sounds), and the most complex ornamentation with runs of up to 13 gracenotes (with particular timing on each!).
I didn't get far into piobaireachd. I did have the somewhat basic but classic "The Desperate Battle" down when a family calamity pulled me away for several years. I was getting ready to take it up again when my job changed and I started being away a lot. I fear that when the travel ends my fingers may be too old and slow for piobaireachd.
Oh yes, you'll be around a bit of Gaelic terminology. But few pipers learn Gaelic -- it is not necessary at all. Still, it's sometimes nice to look at a title such as "Thug Mi Gaol" and know it's not about thugs and jails, but really says "Give Me Love." *\;^)
It's a long road and of every ten who pick up a practice chanter only one makes it to the pipes, but once you get there you've set off on a journey you could never imagine. You will come to have, as they quite literally say in Gaelic, "a piper in you" and later, such stories to tell.
Are you ready to start now? *\:^)