"There's this feature X in my target language... it makes no sense to me, so I will wait for it to magically enter my memory... Not tackling it yet!"
I've seen this mindset repeated over and over by people learning Finnish, especially when it comes to consonant gradation. I myself am a native speaker of Finnish (to the surprise of many, apparently), and most of the languages I had previously studied had nothing similar (or as difficult or "foreign" to understand), so I couldn't really say anything about it.
However, in uni, I started learning North Sámi. It also has gradation, just on a larger level and with different consonants in a different way. This allowed me to form an opinion:
If you don't get it, don't get it. Just memorize it well enough so you know how to apply it and when.
Do not wait or delay learning an important part of the language just because you are scared or confused. Do it scared and confused. If you want to learn the language, learn the language! It's that simple. You can try to start to understand the mechanics after spending 4 hours each night drilling practice questions.
I would naturally apply this to every language one wants to learn, but as I am a blog about Finnish, I'll say; if you do not understand gradation yet, pick your book up! Practice!
I think that this applies to multiple aspects of Finnish and I totally agree. I would also like to add that Finnish is taught usually in a very grammar oriented way. If you like that, cool. But if you do not like that please remember that you do not have to understand or memorize everything right away. Use the language, read it, write it, speak it, listen to it. You will start to learn stuff by heart by pure repetition.
If you can remember all the 40+ declination groups for nouns by heart and also know what noun is in which, nice! That sure gives you a shorthand. But if you do not remember that easily, I am pretty sure that you will start to remember correct forms for at least most common words pretty quickly if you just use the language. It has worked for me at least with every language I have learned.