I am a current applicant, but here are my thoughts....
1.5 years of research seems pretty low to me. You want as much research as possible and more recent experience is probably better. Quality of research also matters, and by quality I mean how much influence you had on decisions and experiments (rather than acting as essentially a tech). I would focus on continuing to get research experience. The rest of your application sounds like it could be great if written well.
Are you continuing your research through to June/July? The extra 6 months would help, I would continue to do research as long as possible to get research hours as high as possible. Applying next cycle may make you a fringe candidate simply because of research, but if you keep doing research and score well on your MCAT a 2020 matriculation seems very likely.