Multiple Adjectives with out ‘and’

I understand how to use multiple adjectives in a sentence if your trying to say for example, "This book is thick and blue", But I do not understand how to say something as in, "I just found kimiko's old japanese lessons". It doesn't sound right in english as 'Japanese and old lessons' but then again it might not translate like this in japnese so i'm just vry unsure'.
I came up with ”きみこの日本語の古いレッスンを見つけたばかり。”
There has also been debate on what word in this kind of situation would be used for 'old'. They are lessons she wrote at least 6 years ago and no one besides my self still has them.

Any help on my word usage is appericated but not as nessacary as just learning how to use adjectives like this.

”きみこの日本語の古いレッスンを見つけたばかり。”
... by itself sounds OK. I'm just wondering what you mean by "lessons," because in Japanese レッスン is either a chapter in a textbook, or the physical classroom teaching session you take. Since you say she "wrote it," I imagine it to be a teaching plan/lesson plan with all the teacher's notes?

In that case, I might rephrase it like:
きみこが以前書いた日本語の教案を見つけたところ（です）。

It was lessons that she wrote on grammer and particles and such to help teach her friends. If that helps any on what word I should use.

OK, I will stick with 教案 (teaching plan) if she's a teacher, 日本語文法の説明 (explanation on Japanese grammar) if she wrote the notes as reference for friends/acquaintance.

Thank you for the advise!

Still my biggest confusion is with how to use multi adjectives in this sort of sentence. =/

Sorry that I did not quite address your original question. (For now I will use the term レッスン to keep things simple.)

日本語の古いレッスン (old Japanese lessons) is fine. 6年前の日本語のレッスン (Japanese lessons from six years ago) is also fine. 6年前の日本語の面白いレッスン (interesting Japanese lessons from six years ago) is also fine.

日本語の and きみこの are not adjectives - simply a noun followed by "no," meaning "of Japanese," in a way. So you can string up a lot of things by adding this の.

If you wanted to say, for example, "Kimiko's old, interesting and fun Japanese lessons," you can say きみこの 古くて おもしろくて 楽しい 日本語の レッスン。When you string up adjectives, i-adjectives take on the ending of "...kute." .. Is this what you wanted to ask about??

If you want to try saying things like "Kimiko's interesting, convenient, and helpful Japanese lessons," you can say きみこの おもしろくて　便利で　役に立つ　日本語の　レッスン. Here I've used one i-adjective (omoshiroi), one na-adjective (benri-na), and one verb phrase that works as a description.

When you string up adjectives, i-adjectives take on the ending of "...kute," na-adjectives take on the ending of "...de." (The one immediately before the noun retains the original form.)

Sorry i was forgetting that the way I was using ’日本語の’wasn't truly a adjective.

With this not being an adjective would it matter grammitcally if i set my adjective(in this case 'old') in front of 日本語 or behind it?

I'm sorry for being so much trouble. Your being an awesome help.

Either 古い日本語のレッスン or 日本語の古いレッスン sounds alright to me.