So A) depending on the state or country’s age of consent and/or Romeo-juliet exceptions, their may or may not be anything legally disallowed by a 16 year old dating and being sexually active with a 19 year old or older.

B) It certainly doesn’t get more morally wrong in your situation where you’re already seeing someone 3 years older than you, as you get older. That difference only becomes less significant as you age.

C) If the age of consent or Romeo-juliet laws do not make a carve out for your situation, and you were dating and sexually active when they were 17 then likely your partner would’ve already been breaking the law before they were an adult. The difference now is that they’d be tried as an adult if they were to be charged.

D) As for the question, is there actually anything wrong with it. In the vast majority of cases, yes, there is something wrong about it, objectively. But also, it’s not necessarily a big problem in the end, sometimws. The problem comes down to three things. 1) Generally speaking, people your age lack real world insight into adulthood and adult relationships and struggle to make mature, rational, long-term-thinking decisions without the overwhelming power of novelty and emotion that comes with young love. I don’t say that to be insulting, just call it the wisdom of hindsight. We were all, to some degree, still kids at your age, and made stupid decisions that many of us regret. That is something an older partner should be cognizant of too, when they are receiving your consent to sexual acts, that your lack of experience means you may not fully appreciate what you are consenting to. 2) Even if you are mature, understand your decisions, and consent with the full understanding and appreciation of what that consent means, the relationship will almost necessarily have an unhealthy imbalance. They being adults typically means that they have more money, more freedom, and more control over the relationship. Truly healthy adult relationships are a partnership been coequal people. 16 year olds are still kids and typically still the responsibility of parents or guardians, still in school, still responsible only for a small fraction of their own care. And many at that age see older partners as a way to jump the line and soup ahead to becoming adults early, but it doesn’t work like that. 3) Even if it is legal, there is a stigma (and not a wholly unjustified one) that your partner will face that you will not. And if it’s not legal, there’s an even huger risk to your partner, losing their freedom, having their name in a sec offense registry, struggling to find homes or jobs, that again, you don’t face. That’s not fair and it’s simply not a good idea and it’s a risk to both partners.

But like I said, it’s not necessarily all that bad. It could be legal, mature, fully consentual, coequal, and neither partner suffers due to the relationship. And it can workout long term. But I do gotta warn you, that is definitely not the norm.