life with army and how to cope with telling parents

My personal advice is do you research - most people are surprised with what the army offers and it isn't all 'boys, bombs and bullets'. People have huge misconceptions about the army, about the way of life, about the job, about how / where you live. Researching all this gives your parents a) the knowledge and understanding that you have done your research and it's something that you want and b) shares that knowledge with them.
The Army has over 77 different trades, from chef, driver, nurse, air dispatcher, HR specialist, cyber engineer etc etc. Basically every job you could think of outside the army (except midwifery) the army pretty much has! The army is the largest provider of apprenticeships in the UK. We are ranked in the top 50 of Top Employers in the UK and is in the Times Top 50 employers for women.
If you do apply, there are lots of different online events that you could join (as well as your parents) which could put yours / their mind at ease too. Good luck with everything. I have 3 daughters and although i'm biased as i love my job and i love being in the army i certainly wouldn't be upset if any of them chose to join - even at the age of 16! It's a great job and if you want to make it a career then there's plenty of scope to do well!

im not 16 im 14 i want to do engerning or be in the front line i have sent the comanding oficer of the cadets an email but they have not repled but i wear glasses will that be a probmlem ?

Hi Emily, it's great that you are thinking already. The reason i mentioned 16 is because you can join the army at 16 (you have to be 15yrs 7 months before you can actually apply though). A 16 year old (up to the age of 17yrs 5mths) would attend the Army Foundation COllege at Harrogate (in Yorkshire) where you would do further studies but also learn how to be a soldier. As you have said you're in cadets you do very similar things (section attacks, kit, drill, basic first aid, fitness etc etc).
Have a look at role finder and look at the different trades there are in the Royal Engineers or the ROyal Electrical and Mechanical Engineers if there's anything there that interests you. Front line could be any trade, any job - it depends on time, on place, on what's happening. If you want to join the infantry females can now do that too. If you are worried about your parents i'd really do your research about joining the infantry as they will want to know why that and not something else, and there's currently also not many females in the infantry at the moment but that will interest will grow BUT it would worry your parents, especially if their understanding is based on what they see and hear off the news / TV etc. Your parents would be very welcome to go and speak with someone in an Army Careers office or perhaps see if your cadets could get someone from the Army Recruiting Group to come and speak with your Cadet unit.