For some, it is the first time they realise how much they have to do and to learn. This will effect them in one of two ways, they will either rise up and go for it or they will shrink back and get tearful and worried.
In an article I wrote some time ago I referred to the time when they will go through 'the crisis of confidence' because reality of what the 11+ entails has dawned on them; it is only after this that we can re-build and then watch the grades increase as their self reliance, self belief and acceptance improves and carries them through.
Stressful for parents, because they want to support and nurture.
The best way to support them is to allow them space to have the crisis and tell me so we can then move the learning to the next stage.
They are not 'frightened' or 'terrified' or any of the words they may use to express how they feel; they are just shocked and worried you may feel they are letting you down - often their only true fear. The best way to support and nurture is to let them know you love them regardless and wont 'tell them off' in the way they feel you might. Its a strange time for them but they have to go through this stress to realise your love and support is as you say unconditional and that their marks wont mean you will 'send them away', 'shout and scream' or 'hate them' all of which I have heard over the years from children terrified of their parent's reactions to things.
They could use their tears to manipulate you into helping them do the test and again this is something to resist. A crying child tugs at the heart strings and you are so desperate to make them feel better, you end up 'taking the stress away', that is, by doing the test with them/for them. Resist!
This is hard love that will give them the independence they will need.
So, they are all in the right place right now, and after the crisis the levels they are at present will become a distant memory and they will improve each time they do a test.
Where should they be in the end? as a rough bench mark;