Firstly, speak with your parents and check they are ok about renting it to you.
Then look at what stock you want to buy in and make sure you know enough about them and their environment to keep them safe and healthy.
Do a business plan inc profit and loss forecast. Make sure you have enough money up front for fencing, stock housing, bedding, feeders, hayracks, water troughs, feed, services (water, electricity, rates, and other running costs). Add on a bit extra for unseen expenditure. Cost out the price of buying in stock including fetching it (you have the vehicles for moving stock? If not, cost it in).
And don't forget to add in all the other costs like buying in ear tags, meds, vet visits, vaccinations, even fuel - or possible loss of stock.
Will you need a loan in order to start up? Any collateral? If so, again - cost it in.
Contingency plan: Look at everything in the worst light - nothing coming in, everything needs looking after/feeding and payments out to be made. Could you get through it?
A lot depends on what stock you buy and who wants it. Do a bit of homework in this regard too. Very important.
Check out registering your business, and obtaining your holders number for registering your stock. There will be fees to pay.
Don't forget national insurance, workplace/stock insurance, pensions - and the tax man.
What is your fall back plan if you are ill? Animals need constant care and attention.
My opinion, the chances of making money? Well, it'll take you quite some time to get back your outlay. And like any business, it might turn a profit, it might not. It depends on how well you manage it. Usually in the beginning the returns for what you are suggesting are little or none, and it will take a while to build the business up. Can you survive in the meantime?
Only you know all the details, do your sums and be honest about the figures you write down.
Good luck. Let us know what you decide and how you get on.