Applicants/Sponsors with a large difference in ages, The rules do not state that the applicant and sponsor must be within a certain age differential, but if there is a disproportionate age difference (for example, more than 25 - 30 years), additional care needs to be taken.
also if you use an agency or lawyer, you will have to pay them, but you will have to supply them with enough evidence to get you a visa, so by doing that, you've already done half of the process, the rest is just filling a form in and double checking you've filled it in correctly