I’m going to say you aren’t ready. When I was 18, I was 185lb and I’m also 6’3 and pretty skinny since i’m 6’3 like you. At 170lbs, you still have a ways you can go natty. I took AAS too early, and I do regret it now. But I also remember how I was at 18, so you probably won’t listen and do it anyways. So this is what I’ll say.
250mg is not enough. Thats TRT doses and you might as well go natty.
Start doing 500mg ew of test. Do not take an AI unless you need it imo, but you probably don’t know enough to feel when you need it and probably to hard headed to go get blood tested like I was. Estrogen is important, you need a healthy level and it does help you grow as well. Low estrogen has negative side effects like killing your libido. You might only need a small dose every 3 days at 500mg or not at all. But everyone is different. Some guys need AI on 200mg ew.
I might add an oral like Dbol or Tbol for 4-6 weeks at 40mg ed. But you don’t need so much to grow at 170lbs at 6’3. Just eat.