How good are these GCSE grades?

Depends on what you mean by 'good' or 'acceptable'; both are highly subjective and relative terms.

C is the minimum grade required for the subject to count as a Level 2 qualification, which is required for future studies. You only have six of those, which is really pushing things, especially as one of them is ICT which is regarded as very soft.

Getting into university doesn't depend on your GCSEs, so in that sense you're in no immediate danger. However, getting into university does depend on your A-levels (or equivalent Level 3 qualifications), and getting into sixth form / college may be difficult with your GCSE results.

I would suggest that you speak to your teachers about the possibility of having some of your exams remarked, and/or about retaking some of them, so that you could hopefully get your grades up at least a bit. And then try to find somewhere that is prepared to let you do A-levels in some sort of sensible subjects. Otherwise you may want to start looking into non-academic alternatives, such as apprenticeships etc.

As others said 'good' is a subjective adjective. My results were significantly higher but if your results are what you need to reach the prospects you desire then they are equally as 'good'. If you're aiming for Oxbridge or a top-top end university I wouldn't bother. But these are acceptable grades for a lot of other universities. I would have thought you may struggle in sixth form, but at least you're eligible to attend.

"Good grades" purely depends if they match and are the required standard for the subject you wish to study, for example, if you got an E in religious studies, but you wanted to study medicine and one day become a surgeon, it isn't going to affect that pathway.

Worry about the grades that you want to develop into a career.