How difficult will it be for me to get into blood spatter analysis?

Not hard but that is just one aspect of Crime Scene Investigations.  I would first get a job as a CSI or a Lab Analyst (latents, DNA, Firearms).  Once in one of these fields, and you are trained to proficiency. Then you can start taking classes and workshops etc in Blood Spatter.    Getting a B.A. or B.S and taking or researching spatter will not lead to doing just that.   It will open the doors for a career in a field I mentioned above. 

As far as I know there are no Blood Spatter experts that do only that and are not a consultant.  I.E work for a lab only.  The experts all started somewhere in a CSI unit or Lab first.

In order to perform BPA (Blood Pattern Analysis), you most likely have to be associated with a forensic laboratory. Most state and local forensic laboratories require a Bachelor's of Science degree, and it is preferred to be in a "hard" science (i.e. Biology, Chemistry, Biochemistry, etc...). Once you've gained employment in said laboratory, BPA is an expertise performed in addition to your normal duties. Very rarely is an analysts sole responsibility BPA. I'm not sure how far along you are in your educational career, but I would highly suggest taking more science and lab based classes and possibly switching your major to a science (probably Biology) related field.

Greetings from Florida! Blood Spatter is a specialty within the Forensics field. To become a Blood Spatter Specialist, depending on your state, you need specific experience and knowledge. For example, in FL a Blood Spatter Analyst requires a focus in biological and chemical sciences. You would would need to obtain an entry level job or internship to gain hands on experience. It will requires a couple of years of experience and further courses. There is also the standard requirements to be hired by an agency. I would suggest that you try to volunteer at a local PD or SO to get your foot in the door. Finding a mentor is key as well because they can groom you to essentially replace them when they retire or move on to better ops. Look up the International Association of Bloodatain Pattern Analyst. They offer courses and training programs.

I really hope this helps. Another tip ia to look at current openings in your area and across the country for the need of your prefered specialty to get an idea of pay, demand etc.

You can do anything that you put your mind too. If you focus on you and yourself and the right things you will do well.

Another note would be to always study your material, tru not have any distractions and just stay focused and do what’s best for you.

My major is biology, I didn't take classes related to blood spatter so I don't know how difficult will it be for me. However, I can learn it if I am accepted as a volunteer.

It's not at all difficult, You can start with single species blood and study it on different surfaces and angles or you can compare difference in various species blood spatter patterns.

not difficult

Not difficult. I have worked with biological samples during my internship at Genok center for biosafety and IMC research laboratory

You would have to find a lab or hospital that would let you specialize in that area. I am taking a phlebotomy course that will result in a certification. I would recommend you taking that approach as well to begin specializing your career path. Your local community college or career building office should have info on how to get started.