I'm the wrong guy to ask on this subject. I've had a tendency all my life to push things too far too fast. Sex for me was often the starting point, not the long awaited moment of real love you are talking about.
I Know When it Felt Right
On the other hand, I know when it has felt right the first time...
I think you have a very romantic notion about sex. In theory, you and your partner should have a degree of trust, connection, compassion, and maybe even love for each other. Some on this site would say for you to wait for marriage...I think this is a mistake.
Sex broadens, deepens, and becomes more pleasurable as your relationship broadens and deepens. But, I think the sexual connection is so important to a lasting, committed relationship, that waiting until you are already bound by marriage could be a recipe for disaster.
So what DO you wait for?
It may be corny to suggest, but when it feels right, you'll know.
For many men, myself included, and I would guess a few women, sex was about proving yourself. It was like a game of chicken. I'm willing to go THIS far, how far are YOU willing to go? Then, you didn't have to take responsibility, it was more like a game. But, I'm not recommending that you play this game. Sometimes in a game, you come out the loser. I guess I believe that sex should always come out with both partners the winners!
Sex Always Complicates a Relationship
But, sex always, always, always complicates a relationship.
Now what? Where are we going as a couple? What does US mean? These are big questions, and for the relationship to sustain the answers, you ought to feel comfortable asking the questions. If you do feel comfortable with deeper questions about where you are going with the relationship, then maybe it's the right time.
On the other hand, if all you're looking for is fun (which I take it you're not), the timing is not important, but the safety precautions are very important.
Guys Depend on Girls to Know When the Time is Right
But really, I'm not sure you should be listening to me. I was always the kind of guy who took his clothes off first and asked questions later. I relied on the young woman to tell me when the time was right. In my defense, there is something to be said for the spontaneous approach. If both partners are willing, ready, safe, and confident, not knowing when the right time is can be kind of exciting!