I don't know about others, but I always suggest learning ALL the letters, numbers, the comma, the period, the error sign(s), the most common Q signals, and some common abbreviations before attempting one's first QSO! But don't let it bother you. Most of us blew at least one of our first ten to twenty QSOs. I blew several of mine. Just remember, SRI OM QRT 73, followed by your call sign and maybe a TU, is always a legitimate way to end a QSO. So, finish learning all the characters you are likely to hear in a typical QSO, and then try again. When you try again, you can try just listening for a while until you can fairly easily follow the QSOs of others. That's what I did; it only took a few days of listening after I learned all the common characters to learn to follow a QSO. The SKCC frequencies are a good place to get slower-speed CW copy.