Glad to hear you are taking steps to improve your situation
Instead of telling someone it’s none of their business you could say ‘I had a seven year relationship but we were both very focussed on our very separate studies and careers and it eventually ended. I’m now in a place where I’m more able to get put and date again as my studies are no longer so demanding’. If they specifically ask about physical stuff I would say ‘yeah I’d love more of that with the right person some time too! It’s been a while!’ If they ask how long just say ‘too long!’ As long as you don’t sound creepy, just jokey and light..
That’s me, maybe think what works for you... when you meet the right girl you can discuss it after you get to know each other.