I'm a french man of 55 years old. I have learnt English a long time ago (that I use daily), but also spanish, Italian, Corsican, a bit of Russian and Hebrew. Then, for reasons which remain unknown, including for me, I decided to learn Chinese and litteraly fell in love with writing characters : I could not know it yet, but I think I had caught the virus of this language, as maybe you do too if you are reading this comment.
I finally found out this website and decided to give it a chance and I will make it short : I highly recommand it. After 2 weeks, I am already able to read, say and understand lots of words and sentences and it was not the case before I joinned this programm. Above all, I have a feeling of constant improvement, which is clearly related to the method used here. Grammar lessons are explained the simplest way, with a minimum of words, and always go straight to the point.
Learning chinese is famous for being one of the most difficult language to learn for a non native so no one will do the job without lots of personal work (2200 hours are required for reaching a decent level) : but if you want to give you a chance to succeed, my opinion is that "Learn Chinese Online" is a very good place to be. I haven't finished the level 1 (I've done only about 50% of the programm) but yet I can say that, starting from absolutely nothing (except the few characters I had learnt before, through the list of vocabulary for HSK 1), I have found here a very efficient method and tremendously increased my skills.
The tests are just part of the learning process, and luckily, you might be big enough for not having to justify yourself in front of anyone (except of yourself). So don't spend a lifetime on grammar lessons and learning new words (though of course this is something you will definitely have to do : just don't spend months on every lesson) and pass the tests at the end of every chapter : if you feel it's still too hard, don't send your answers, go back to your personal work of learning and memorization, but most of the time, you will see by yourself that you are maybe better than you imagined.