Yes, Relearning to play the trumpet is an entirely different ball of wax then learning it first time around! A mouth reed instrument is not like a woodwind. many people have taught themselfs to play a flute, recorder, guitar etc all on their own with never a teacher involved. The trumpet though is not an instrument to self teach yourself it will not work. Now if you had played for 8-10 years then stoped then comeing back would be doable but not to just teach oneself from scratch! As much as I am pro do it yourself the esources are not their for this type of goal on the trumpet. If you seriously love music and want to teach yourself I would seriously recomend something like an Alto Recorder if you are a grown up since that is going to be rather man sized. I like the wooden one's but a one piece plastic one will work too just stay away fromt he cheap dollar store multi-piece plastic ones they are crudely made and seldom play in tune. I taught myself to play a closed hole flute since fingering is the hardest part well that an breath control. Just so you understand why I am recommending high end recorder's and such is becasue they generate the base tone for you just by their design their is no need for highly developed lip muscles and cordination of the lips. The hardest part is learning the fingerings for each note, reading music,and learning to count. SInce most recorder music is usualy based off song's with words or lyrics getting the phraseing right is as simple as singing the song. A well made recorder or Irish wooden flute for instance can sound very beautiful and are learnable with out a teeacher. I doubt you will be able to self teach yourself trumpet. Why set yourself up to fail? The best part is that recorder's can easily be packed and can easily be made to do just about anything you want from camp fire sing along's to playing for yourself in the woods etc.... They are not that loud so neigbor's do not complain. If you wanted to play for a girl you could easily play a romantic piece in a park and not disturb anyone else try that with a trumpet! Even played softly if your outside in a park people 300 yards away can probably hear you.