You're very welcome, Di - that's what I love coming on here for - giving advice. You're not old at 47, I'm 45 and still running relatively quickly, although it does take more of an effort now!
In terms of 'respectable times', I say anything under 30 minutes for 5K is good, under 25 minutes is very good and under 20 minutes is superb. Given the right training programme and diet regime, I think anyone is capable of going sub 20 minutes - if I can do it then anyone can!
Of course you can run 10K, you can do anything if you set your mind to it!