I believe that every one can understand the meaning. But in eveyday we native speaker dont say that in that way."起先"means in the beginning. We often say,刚开始

“起先”是北方方言，对于北方人来说，很自然的说法。但普通话时可能觉得不太自然。

也还可以，能理解意思，就是在语句上有些许别扭

It is correct. But normal people don't use "起先” instead of "一开始“. "起先” sounds like old Chinese or opera dialogue. Most of Chinese don use this word. But your sentence is correct and good. Cheers.

”起先学汉语很难，可是我越学越喜欢。“ 这句话里“起先”合适吗？ ^^起先不太合適，可能 [ 開頭 ] 或者 [ 一開始 ] 會比較適合。 “學漢語開頭很難，可是(後來發現)我越來越喜歡。” / “一開始學漢語很難，可是(後來發現)我越來越喜歡。“ 希望對你有幫助！