Getting a first analyst job in Investment Banking at 26

Hey guys, I'm looking for some advice on my situation and what can be done to get to where I need to be. Very briefly, I worked in Business Development for 3 years and realised this wasn't a career choice if I wanted a fulfilling life of learning and financial reward (I've done my homework onto the work life of IB and this is 100% what I want to do with my life). Realising this I went to university an got a 2.1 in International Business and moved to Canary Wharf (A financial district in the UK). I've also worked full time since I was 18 in restaurants as a second income, but I don't feel like this holds much relevance.

Main Questions: 1) Since I have no financial backgroud, I plan to do the Investment Management Certificate (As advised by alumni). Would this help significantly in getting a position / internship? 2) Is getting an analyst position possible without an internship or relevant experience? (If I taught myself modelling for example) 3) What is the probability of getting an internship at 26? 4) Obviously I will shoot for both, but is it possible to get into a BB at this stage? Or should I focus all of my energy on a Boutiques?

Apologies for the long post and thank you for taking the time to read.