Young love

Why do adults always say that teenagers don't understand what love really is? I'm 16 almost 17 and I have always had people tell me I am so much more mature for my age or I have a "old soul". I have been with my boyfriend for 2 years (he's 17) and he makes me ridiculously happy. I love him so much and he's my best friend and our relationship is also more realistic than people my expect for a couple of teenagers and we have even started making future plans together. It just hurts when I hear people tell me that my love for him isn't real because we are so young and they don't even know what our relationship is really like. Comments please☺️