For adults, is it appropriate to practice brush writing or pen writing first?

It is recommended to practice writing brush first, because it is very beneficial to brush words after writing brush words, such as shelf structure and using a pen. You can use the words of Ou Yangxun and Liu Gongquan. Bookstores also have this kind of copybook, which is very suitable for beginners. However, I suggest listening to Professor Tian's calligraphy lecture, 150, which contains many calligraphy skills and is worth learning. Practice regular script with a brush. It is recommended to use double wool and weasel hair, which is more suitable for practicing regular script, and the strokes do not need to be too long.