This is totally normal Hatwoman - your first ever student crits will be weak because you had to prepare without much support and were probably pushed for time. Then the next time you do it they will be better, because your teaching will have improved objectively and because you will have worked out what it is that your particular group of students like and don't like.
My first ones were so bad that our lovely office administrator hid them until I had finished all my teaching for that term, so I wouldn't be put off. Then fortunately the next ones I got were much, much better.
If there are any that are really unkind and not constructive, then that says more about the students who wrote them than about you, because they all know they should phrase them in a way that helps you improve, so you don't need to take them too seriously. Take note of any that say something specific enough to give you something to work on. It is a good idea to sort out the good ones and maybe go through and copy out all the nice things that have been said about you, because you might want to quote from them in job applications in the future.
You will also want to have a general picture of how you're doing so you can track your improvement, so it's a good idea to count them up and work out your average score, but it's really just to help you - it's very difficult to make meaningful comparisons with other lecturers, because you are all teaching different material, some of which students like more, and at different times in the course (earlier lectures tend to get more extreme grades). There was also some research reported by the THES a few years back which demonstrated that students tend to rate lecturers higher if they are of a similar age/sex/race to them . And of course there is the issue of questionnaire design and how that affects results.
Quite frankly though, if you have got some that say you are fantastic you are probably doing very very well and don't have too much to worry about.