I've learned Japanese beginning at at age 18 and eventually becoming fluent enough to pass the JLPT N1 (Japanese Language Proficiency test) and work in International Relations with the Japanese government (I'm 36 now, btw). I'll try to give you some info.
I wouldn't say Japanese is harder to learn than other languages. True, it has a reputation for being difficult, but I think that's mainly due to it's convoluted writing system (I have heard linguists refer to it as the most difficult in the world). In addition to 2 phonetic systems, it also uses around 2000 Chinese characters (Kanji), which have been adapted, altered, and reinterpreted to fit the Japanese language (while also adopting the Chinese pronunciations and meanings on top of it), so most of the Kanji has multiple pronunciations and meanings depending on how it's used and what characters they are combined with, and the only way to know is through hard memorization. There are no mnemonics or rules to help you, just repetition and memorization. Japanese people formally study Kanji all through high school, and that's in addition to a lifetime of natural exposure to it, so you can imagine how daunting it would be for a non-native learner. I still need to look up words when I read.
This is why I would recommend to not worry about learning Kanji, at least not right away. Hiragana and Katakana (the phonetic systems) are pretty simple and easy to get down. Learn those first and look up the kanji as you encounter them. A lot of literature aimed at youth (i.e. manga) has the reading for Kanji written above it in hiragana, which makes reading and learning much easier. Nowadays it's shouldn't be too difficult to find libraries or stores that have manga in Japanese.
Anyway, while reading is admittedly a challenge, I honestly think speaking is not all that bad. Pronunciation is pretty simple. Japanese actually has a very small variety of sounds compared to other languages (I learned in linguistics class that it has roughly 1/10 of the sounds that can be produced in English). Every sound in Japanese exists in English in some form, so you don't have to train yourself to make new sounds or anything. People seem to have the most trouble with the Japanese "R," as it's not really close to the English "R," or "L" for that matter; it's a unique sound that's actually closer to an English "D" than an "R" or "L" (Imagine positioning your tongue like you're making an "L" sound but instead making a "D" sound (if that makes sense, it's a crappy explanation)). Grammar is not that bad to get down, either. It seems confusing and "backwards" at first, but I had a much easier time once I realized how consistent and easy the sentence structure is (i.e the main verb comes at the end of the sentence).
Textbooks like "Genki" (https://www.amazon.com/GENKI-Integrated-Elementary-Japanese-English/dp/4789014401
) are so good you could learn a lot all by yourself. I began self-learning with a book called "Japanese for Everyone" (https://www.amazon.com/Japanese-Everyone-Functional-Approach-Communication/dp/4889962344
) and learned enough to test into 2nd year Japanese when I started college classes.
Duolingo is a simple, easy, and free. That wouldn't hurt to try. Rosetta Stone is good to help you remember and retain words and phrases, but it doesn't become practically useful until you get pretty deep into it, so you need to stay motivated and stick with it if you want to get something out of it.
I lost track, so I'm going to end here for now. Hopefully this was a bit helpful. Feel free to ask questions or send me a message.