Peronsonally, I’d want to date someone for 2-3 years before getting engaged. Generally speaking, I think all couples, regardless of age, should wait at least a year before getting engaged. I think the younger a couple is (early 20s, for instance), the longer they should date before getting engaged or married because people change and grow a LOT in their early and mid-20s. But for some people, it’s a goal to marry young.
I wouldn’t want a terribly long engagement, BUT I’d also want a no-fuss wedding — so it’s not like I’d need all that time to plan.
That said, there are no guarantees that waiting a long time guarantees a lasting loving marriage, or that NOT waiting means you’re doomed. My ex’s parents met when they were 23 and were engaged within 3 months of meeting one another. They had (and I presume still have) a wonderful marriage in spite of that. On the flip side, my parents have known each other since high school, they waited until they were in their late 20s to get married, and now hate one another. You always run the risk that your marriage won’t work out for a number of reasons.
So yeah, I don’t think I’m terribly wise about this subject. To each their own, I guess, but the idea of getting engaged to someone too soon gives me anxiety just to think about.